Aetna considers specific allergy testing and allergy immunotherapy medically necessary for members with clinically significant allergic symptoms.  Based on a review of the medical literature and the position statements of scientific organizations in the field of allergy and immunology, Aetna considers the specific allergy testing and treatment described below medically necessary in accordance with the selection criteria noted.

1. ALLERGY TESTING

   1. Aetna considers the following allergy tests medically necessary:

      Epicutaneous (scratch, prick or puncture) when IgE-mediated reactions occur to any of the following:

      1. Foods; or
      2. Hymenoptera (stinging insects); or
      3. Inhalants; or
      4. Specific drugs (penicillins and macromolecular agents).

      Intradermal (Intracutaneous) when IgE-mediated reactions occur to any of the following:

      1. Foods; or
      2. Hymenoptera venom allergy (stinging insects); or
      3. Inhalants; or

      4. Specific drugs (penicillins and macromolecular agents).

      Number of epicutaneous (percutaneous) and intracutaneous (intradermal) skin tests:

      The evaluation of inhalant allergy may require up to 70 percutaneous tests, followed by up to 40 intracutaneous tests (which are usually performed when percutaneous tests are negative).  However, in most cases, fewer tests are required.

      Skin Endpoint Titration (SET) (also known as intradermal dilutional testing (IDT)) for determining the starting dose for immunotherapy for:

      1. Members highly allergic to hymenoptera venom allergy (stinging insects); or
      2. Members highly allergic to inhalants.

      Number of SET tests:

      It is inappropriate to use SET in place of skin testing; however, when used to determine the starting dose for immunotherapy in highly allergic members, up to 14 titration tests may be necessary.  An additional 40 antigens or 80 IDT injections may be medically necessary if any of the initial test results is positive.

      Skin Patch Testing for diagnosing contact allergic dermatitis.

      Photo Patch Testing for diagnosing photo-allergy (e.g., photo-allergic contact dermatitis).

      Photo Tests for evaluating photo-sensitivity disorders.

      Bronchial Challenge Test for testing with methacholine, histamine or antigens in defining asthma or airway hyperactivity when either of the following conditions is met:

      1. Bronchial challenge test is being used to identify new allergens for which skin or blood testing has not been validated; or
      2. Skin testing is unreliable.

      Exercise Challenge Testing for exercise-induced bronchospasm

      Ingestion (Oral) Challenge Test for any of the following:

      1. Food or other substances (i.e., metabisulfite); or

      2. Drugs when all of the following are met:

         1. History of allergy to a particular drug; and
         2. There is no effective alternative drug; and

         3. Treatment with that drug class is essential.

      In Vitro IgE Antibody Tests (RAST, MAST, FAST, ELISA, ImmunoCAP) are considered medically necessary for:

      • Allergic broncho-pulmonary aspergillosis (ABPA) and certain parasitic diseases; or

      • Food allergy; or
      • Hymenoptera venom allergy (stinging insects); or
      • Inhalant allergy; or
      • Specific drugs.

      Number of Tests:

      In vitro tests may be medically necessary for the initial allergy screen in lieu of skin testing.  An initial allergy screen is 12 tests.  Additional tests may be medically necessary if any of the initial test results is positive.  If all test results are negative, additional testing beyond the initial allergy screen of 12 tests/allergens is not considered medically necessary.

      Total Serum IgE for diagnostic evaluation in members with known or suspected ABPA and or hyper IgE syndrome.

      Lymphocyte transformation tests (lymphocyte mitogen response test, PHE stimulation test, lymphocyte antigen response assay) are considered medically necessary for evaluating persons with sensitivity to beryllium.  Lymphocyte transformation tests are considered experimental and investigational for evaluation of persons with allergies or other hypersensitivities.  Note: Lymphocyte transformation tests are also considered medically necessary for evaluation of persons suspected of having congenital or acquired immunodeficiency diseases affecting cell-mediated immunity, such a severe combined immunodeficiency, common variable immunodeficiency, X-linked immunodeficiency with hyper IgM, Nijmegen breakage syndrome, reticular dysgenesis, DiGeorge syndrome, Nezelof syndrome, Wiscott-Aldrich syndrome, ataxia telangiectasia, and chronic mucocutaneous candidiasis.  Lymphocyte transformation tests are also medically necessary for evaluation of persons with thymoma and to predict allograft compatibility in the transplant setting.  For lymphocyte transformation testing for infertility, see CPB 0327 - Infertility.

      Allergy Re-testing: Routine allergy re-testing is not considered medically necessary.

   2. Aetna considers the following tests for allergy testing experimental and investigational as they have not been proven to be effective:

      1. ALCAT test
      2. Anti-Fc epsilon receptor antibodies testing
      3. Anti-IgE receptor antibody testing
      4. Candidiasis test
      5. Chlorinated pesticides (serum)
      6. Clifford materials reactivity testing
      7. Complement (total or components); (may be appropriate in autoimmune disorders, complement component deficiencies, hereditary angioedema, vasculitis)
      8. C-reactive protein (may be appropriate in inflammatory diseases)
      9. Cytotoxic food testing (Bryans Test, ACT)
      10. Electrodermal acupuncture
      11. ELISA/ACT
      12. Eosinophil cationic protein (ECP) test
      13. Food immune complex assays (FICA)
      14. IgG RAST/ELISA testing
      15. Immune complex assay (may be appropriate in autoimmune disorders, systemic lupus erythematosus, vasculitis)
      16. Leukocyte antibodies testing
      17. Leukocyte histamine release test
      18. Lymphocytes (B or T subsets); (may be appropriate for collagen vascular disease, immune deficiency syndromes, leukemia, lymphomas)
      19. Mediator release test (MRT)
      20. Muscle strength testing or measurement (kinesiology) after allergen ingestion
      21. Ophthalmic mucous membrane tests/conjunctival challenge tests
      22. Prausnitz-Kustner or P-K testing -- passive cutaneous transfer test
      23. Provocative nasal test (also known as nasal provocation testing)
      24. Provocation-neutralization testing (Rinkel Test) either subcutaneously or sublingually
      25. Pulse test (pulse response test, reaginic pulse test)
      26. Rebuck skin window test
      27. Sublingual provocative neutralization testing and treatment with hormones
      28. Testing for electromagnetic sensitivity syndrome/disorder (also known as allergy to electricity, electro-sensitivity, electrohypersensitivity, and hypersensitivity to electricity)
      29. Testing for multiple chemical sensitivity syndrome (also known as idiopathic environmental intolerance (IEI), clinical ecological illness, clinical ecology, environmental illness, chemical AIDS, environmental/chemical hypersensitivity disease, total allergy syndrome, cerebral allergy, 20th century disease)
      30. Venom blocking antibodies
      31. Volatile chemical panels (blood testing for chemicals).

      32. Tests listed in section I.A., when performed for indications not listed as medically necessary.

2. ALLERGY IMMUNOTHERAPY

   1. Aetna considers allergy immunotherapy medically necessary for the treatment of the following IgE-mediated allergies:

      1. Allergic (extrinsic) asthma
      2. Dust mite atopic dermatitis
      3. Hymenoptera (bees, hornets, wasps, fire ants) sensitive individuals
      4. Mold-induced allergic rhinitis
      5. Perennial rhinitis
      6. Seasonal allergic rhinitis or conjunctivitis

      when all of the following conditions are met:

      1. Member has symptoms of allergic rhinitis and/or asthma after natural exposure to the allergen; or
      2. Member has a life-threatening allergy to insect stings (bees, hornets, wasps, and fire ants), and
      3. Member has skin test and/or serologic evidence of IgE-mediated antibody to a potent extract of the allergen, and
      4. Avoidance or pharmacologic therapy can not control allergic symptoms or member has unacceptable side effects with pharmacologic therapy.

      Note: Also see CPB 0670 - Xolair (Omalizumab).

   2. Aetna considers allergy immunotherapy experimental and investigational for all other indications, including the following because its effectiveness for these indications has not been established:

      1. Angioedema
      2. Atopic dermatitis (cover for dust mite atopic dermatitis)
      3. Chronic urticaria
      4. Food allergy
      5. Intrinsic (non-allergic) asthma
      6. Migraine headaches

      7. Non-allergic vasomotor rhinitis.

3. OTHER TREATMENTS

   1. Aetna considers the following treatments medically necessary:
      
      Rapid desensitization (a.k.a., rush, cluster or acute desensitization) for members with any of the following conditions:

      1. IgE antibodies to a particular drug that can not be treated effectively with alternative medications; or
      2. Insect sting (e.g., wasps, hornets, bees, fire ants) hypersensitivity (hymenoptera); or

      3. Members with moderate to severe allergic rhinitis who need treatment during or immediately before the season of the affecting allergy.

      Rapid desensitization is considered experimental and investigational for other indications because its effectivenes for indications other than the ones listed above has not been established.

      Note: If a woman is contemplating pregnancy and requires initiation of allergy immunotherapy and/or it is anticipated that she will require allergy medications that may increase risk to her or the fetus, rapid desensitization is an acceptable approach.

      Epinephrine kits (e.g., Ana-Kit, Epi-Pen auto-injectors) to prevent anaphylactic shock for individuals who have had life-threatening reactions to insect stings, foods, drugs or other allergens or have severe asthma or if needed during immunotherapy.  Epinephrine kits are considered experimental and investigational for other indications because their effectivenes for indications other than the ones listed above has not been established.
      
      Aspirin Desensitization is considered medically necessary for aspirin sensitive persons who require administration of ASA or ASA-like drugs (aspirin avoidance is not possible) in the setting of:

      1. refractory rhinosinusitis or nasal polyposis recurring after surgery; or
      2. stable cardiovascular disease requiring thromboembolic prophylaxis; or
      3. antiphospholipid syndromes during pregnancy; or
      4. poorly controlled asthma.

      Aspirin densensitization is considered investigational/experimental for any other indication.

   2. Aetna considers the following treatments experimental and investigational as they have not been proven to be effective:

      1. Acupuncture for allergies
      2. Allergoids (modification of allergens to reduce allergenicity)
      3. Autogenous urine immunization (autogenous urine therapy)
      4. Bacterial immunotherapy
      5. Detoxification for allergies
      6. Ecology units/environmental control units/environmental chemical avoidance for multiple chemical sensitivity syndrome
      7. Enzyme potentiated desensitization (EPD)
      8. Helminth Trichuris suis therapy for allergic rhinitis
      9. Homeopathy for allergies
      10. Neutralization therapy (desensitization neutralization therapy)
      11. Neutralizing therapy of chemical and food extracts
      12. Oral nystatin for the treatment of "candidiasis hypersensitivity syndrome"
      13. Photo-inactivated extracts
      14. Polymerized extracts
      15. Poison ivy/poison oak extracts for immunotherapy in the prevention of toxicodendron (Rhus) dermatitis
      16. Repository emulsion therapy
      17. Rhinophototherapy
      18. Sublingual drops/sublingual immunotherapy
      19. Treatments for electromagnetic sensitivity syndrome/disorder
      20. Ultra low dose enzyme activated immunotherapy (low dose allergens or LDA).

Allergy is a hypersensitive reaction that is usually manifested in the clinical form of allergic asthma, hay fever or eczema developing within minutes to a few hours after exposure to an antigen.  The most common types of allergies are rhinitis, asthma, food allergy, insect sting allergy, drug allergy and contact dermatitis.  Allergy testing is focused on determining what allergens cause a particular reaction and the degree of the reaction and provides justification for recommendations of specific avoidance measures in the home or work environment or the institution of particular medicines or immunotherapy.  There are virtually no age limitations for performance of skin tests.  However, skin test reactivity may be diminished in infants and the elderly.  Types of allergy testing include in vivo, in vitro, provocation testing, and controversial allergy tests.

1. Allergy Testing

   1. In-Vivo Diagnostic tests of IgE dependent reactions

      Epicutaneous (Scratch, Prick or Puncture) and Intracutaneous In-Vivo Diagnostic Skin Tests

      Skin tests for IgE-mediated disease with allergenic extracts have been shown to be effective aids in the assessment of allergic patients.  These tests involve the introduction of small quantities of test allergens below the epidermis.  Within 15 to 20 mins, a characteristic wheal and flare reaction occurs in patients sensitive to one or more of the test allergens.  The majority of allergists use prick or puncture and/or intracutaneous skin tests, since the amount of allergen delivered by these methods is better controlled than by scratch tests.  Although skin testing is considered to be a safe procedure, adverse events, such as large local reactions and systemic symptoms may occur in extremely sensitive individuals.  Deaths from anaphylaxis after skin testing have been reported.  These extremely rare systemic symptoms are less likely to occur with prick or puncture than with intracutaneous tests.  Prick or puncture tests are generally considered to be the most convenient, least expensive and most specific screening method for detecting the presence of IgE antibodies in patients with appropriate exposure histories.  Prick or puncture tests are generally less sensitive than intracutaneous tests.  For inhalant allergens, prick or puncture tests are generally felt to correlate better with the presence of clinical allergy.  However, intracutaneous (within the skin) testing may detect relevant sensitivity and should be considered when the prick or puncture test is negative or equivocal to allergens strongly suggested by the patient's history or exposure, or when skin sensitivity may be decreased such as in infants or older patients.  Intracutaneous tests permit identification of a larger number of clinically reactive patients, especially those with lower skin test sensitivity.

      Skin testing to drugs is generally unreliable, except for the penicillins and macromolecular agents, such as foreign antisera, hormone (e.g., insulin), enzymes (e.g., L-asparaginase, streptokinase, chymopapain), and egg-containing vaccines.

      In January 2003, the Board of Directors of the American Academy of Otolaryngic Allergy (AAOA) endorsed strategies for testing for inhalant allergy (Krouse and Mabry, 2003), stating that “[m]embers should practice in ethical and fiscally responsible ways.”  The AAOA provided the following guidelines on the necessary number of tests for inhalant allergy (e.g., prick testing, intradermal testing, intradermal dilutional testing (IDT), and in vitro testing):

      1. Screening: Screen with no more than 14 relevant antigens plus appropriate controls.
      2. Antigen survey: If screening is positive and immunotherapy is contemplated, use no more than 40 antigens.  More extensive testing may be justified in special circumstances.

      3. Quantification for safe starting point: Use no more than 80 IDT tests routinely.  More extensive testing may be justified in special circumstances.

      Skin Endpoint Titration (SET)

      Skin endpoint titration (SET) (also known as intradermal dilutional testing (IDT)) is intradermal testing of sequential and incremental dilutions of a single antigen.  SET involves serial testing with several dilutions of a single treatment allergen or mixture of allergens to identify the lowest dilution that produces a positive skin reaction. In performing the test, wheals of identical size are made in the most superficial layers of the skin and measured for uniformity.  The first wheal is made with approximately 0.1 ml of a dilution estimated to be too weak to produce symptoms.  Successive wheals are made with serial dilutions, each generally five times stronger than the previous one, until negative responses are replaced by positive responses of increasing size.  The "endpoint" is the weakest dilution that produces a positive skin reaction and initiates progressive increase in the diameter of wheals with each stronger dilution.  Proponents of SET emphasize that it quantifies skin testing and replaces a single equivocal reaction with a progressive pattern easily identified.  When immunotherapy is initiated, starting with too strong an extract may precipitate dangerous allergic reactions, while starting with one too weak may delay treatment results.  Skin endpoint titration allows the initiation of immunotherapy with a safe but relatively potent dose, and allows the beginning dosage for each positive responding allergen to be varied depending on its specific “endpoint.”  Although traditional allergists often rely on single dilution “classical” testing, they have accepted SET over the last decade as effective for quantifying patient sensitivity and for providing a guide for a safe starting dose for immunotherapy noting that studies have not shown it to be an effective guide to a final therapeutic dose.  The AAOA also has advised that costly, repetitive endpoint titrations are usually unnecessary because, regardless of what the titration indicates, the dose will be advanced either until the patient can tolerate no more or until a dose is reached that produces satisfactory results.  Skin endpoint titration is considered the gold standard of skin testing by the AAOA; the American Medical Association’s Council of Scientific Affairs also is on record that SET is helpful for the delineation of patient-specific sensitivity to various antigens as well as to evaluate a patient’s response to various forms of immunotherapy.  They note that controlled studies have shown that the intradermal method of SET is effective for quantifying sensitivity to ragweed pollen extract and for identifying patients highly sensitive to ragweed.

      While allowing that SET is a valid method for obtaining semi-quantitative information about a person's sensitivity and for determining a safe beginning dose for immunotherapy, the American College of Physicians (ACP) advises that the primary use of SET is to identify hymenoptera venom (yellow jacket, honey bee, hornet, wasp, fire ant) sensitivity and to determine the safe starting dose for venom immunotherapy.

      In a guideline, revised in 2003, the AAOA recommends screening prick tests with relevant antigens to determine which to use in subsequent SET (Krouse and Mabry, 2003).  The literature on screening supports, and the AAOA recommends, usually screening and billing for no more than 14 antigens (plus the appropriate controls) for an initial allergy evaluation.  In most geographic regions, a range of up to 14 allergens is sufficient to check the most prevalent molds, dust components, grasses, trees, animals, and weeds.  If screening is positive and immunotherapy is contemplated, the AAOA recommends no more than 40 antigen be tested unless indicated by unusual clinical circumstances.  For SET, the AAOA says that up to 80 injections are usually necessary to identify the offending antigen and find a safe starting point for immunotherapy.

      Provocation (Challenge) Testing

      In provocation or challenge testing, a suspected allergen in a clinically relevant exposure is administered in an attempt to reproduce symptoms.  Challenge tests have been broadly applied under research conditions for many years, but there also may be clinical situations in which they can be useful for confirmation of clinical disease.  Considerable experience with these methods is required for proper interpretation and analysis.

      Patch Testing

      Patch testing is an accepted method of differentiating allergic contact dermatitis and irritant contact dermatitis.  Twenty to 30 antigens are used in the usual routine screening panel of patch tests.  The patches are removed after 48 hours and an initial reading is taken 1 hour later.  The final reading is taken a further 48 hours later.

      Photo Patch Testing

      Some chemicals or medications (e.g., lomefloxacin, ofloxacin, ciprofloxacin and norfloxacin) produce an allergic reaction only when exposed to light (usually ultraviolet type A, UVA).  Patients who are over-sensitive to light and those with a rash that appears on parts of the body normally exposed to light but that does not appear in areas shielded from the light should have a photo-patch test.  With photo patch testing, 2 identical sets of allergens are placed onto the patient's back on day-1.  One of the sets is exposed to UVA light, and the sites are then examined as described above for patch testing.  A positive photo patch test is recorded when an allergic reaction appears only on the light-exposed site.

      Photo Tests

      Photo testing is skin irradiation with a specific range of ultraviolet light.  Photo tests are performed for the evaluation of photosensitivity disorders.

      Bronchial Challenge Testing

      Bronchial challenge testing with methacholine, histamine, or allergens is an accepted method of defining asthma or airway hyperactivity when skin testing results are not consistent with the patient's medical history.  Results of these tests are ordinarily evaluated by objective measures of pulmonary function and occasionally by characterization of bronchoalveolar lavage samples.  Recommended dosage is an incremental increase of pharmacologic dose until a response is produced.

      Exercise Challenge Testing

      Exercise challenge testing is an accepted method of diagnosing exercise induced bronchospasm in asthmatic and non-asthmatic patients.

      Ingestion (Oral) Challenge Testing

      Ingestion (oral) challenge testing is an accepted method of diagnosing allergies to food, drug or other substances (i.e., metabisulfite).  Drug challenge testing should not be confused with cutaneous or sublingual provocation and neutralization therapy, which is a non-covered modality.

      Nasal or Conjunctival Provocative or Challenge Tests

      Nasal or conjunctival provocative or challenge tests employed for the diagnosis of either food or inhalant allergies, involve the direct administration of the allergen to the mucosa.  The patient is then observed for signs and symptoms and the presence of symptoms is interpreted as a positive indication of allergies.  These tests are time consuming, only 1 antigen may be administered per session, a non-standardized quantity of allergen is administered and they have the potential of inducing severe symptoms.  There is currently no standard of techniques for nasal or conjunctival challenge tests that can be applied to clinical practice.

      Prausnitz-Kustner or P-K Testing

      Prausnitz-Kustner testing has been used in patients with dermatographia or generalized skin eruptions.  A control site on the forearm of a non-allergic recipient is selected.  This site is injected intradermally with allergy serum from a patient on whom direct skin tests cannot be done.  Allergenic extract is later injected intradermally into the initial injection site of the recipient and observed for the development of a wheal and flare.  Because of the risk of transmitting hepatitis or AIDS, this test is contraindicated.

      Provocation-Neutralization (Rinkel Test)

      Provocation-neutralization is a method of testing for the presence of food, inhalant or environmental chemical allergies by exposing the individual to test doses of these substances intradermally, subcutaneously, or sublingually with the purpose of either producing or preventing subjective symptoms.  Provocation-neutralization evolved from the serial end-point titration skin testing procedure (a covered modality), and is based on the concept that extremely small quantities of allergens can cause immediate disappearance (“neutralization”) of ongoing symptoms.  Once a test is considered positive (results are interpreted either by subjective symptom provocation or objective skin whealing), a progressive series of lower concentrations are administered under the tongue or skin until a dose is reached at which the patient reports no sensations.  This amount of the test substance is considered the “neutralizing dose”, which is then used for future treatment.  Sublingual testing has been used mainly in diagnosing food allergy, although extracts of chemicals, inhalant allergens, drugs, and hormones have been administered by the sublingual route.  Published literature frequently combines the discussion of testing and treatment as a single entity.  Provocation-neutralization is used by those physicians who subscribe to the concept of multiple food and chemical sensitivities (also known as idiopathic environmental intolerance's (IEI), clinical ecological illness, clinical ecology, environmental illness, chemical AIDS, environmental/chemical hypersensitivity disease, total allergy syndrome, cerebral allergy, 20th century disease) and “delayed food allergy”.  When used for the latter, provocative testing may be identified as the intracutaneous progressive dilution food test (IPDFT).  Since provocation-neutralization requires the provoking and neutralizing of symptoms to a single item at a time, the patient could be required to undergo hundreds of individual tests requiring weeks or months of full-day testing.

      Traditional allergists believe that food hypersensitivities are primarily IgE-mediated and treat with avoidance diet and/or drug therapy.  Diagnosis is by history, elimination diets, skin tests, or food challenge.  Non IgE-mediated food intolerance is classified as non-immune adverse reactions to food of a pharmacologic (caffeine, histamine, tyramine, serotonin, dopamine, etc.); metabolic (lactose intolerance); or idiosyncratic nature, e.g., food dyes, preservatives (sulfites), flavor enhancers (MSG).  The AAOA indicates that provocation-neutralization techniques were developed primarily for these delayed, less obvious, non-IgE-mediated food hypersensitivities and not for confirmation of immediate food allergy obvious by history.  Test substances have also included chemicals such as formaldehyde and alcohol, histamine, tobacco, newsprint and inhalant allergens.

      Sublingual provocative neutralization with hormones utilizes the same principles as noted above and involves preliminary extensive blood testing for allergies to hormones and the subsequent administration of small doses of hormones suspected of causing the allergic symptoms.  There have been no well-controlled studies that have shown this procedure to be effective in the diagnosis and treatment of symptoms thought to be caused by allergy to hormones.

      Both the ACP and the American Academy of Allergy and Immunology (AAAI) consider provocation-neutralization therapy an unproven modality.  In a Training Program Directors' Committee Report on Controversial Practices published by the AAAI, provocation-neutralization testing and neutralization therapy are listed as unproven.  The AMA's Council on Scientific Affairs, based on the reports in the peer-reviewed scientific literature, stated that there are no well-controlled studies establishing a clear mechanism or cause for multiple chemical sensitivity syndrome.  More importantly, there are no well-controlled studies that have demonstrated either diagnostic or therapeutic value for provocation-neutralization therapy.

      Provocation-neutralization must not be confused with the recognized forms of target-organ challenge testing (bronchial, ingestion, patch testing), which are covered modalities.

   2. In-Vitro Testing

      RAST/MAST/PRIST/RIST/FAST/MRT/VAST/ELISA/ImmunoCAP

      For most allergens, in-vitro allergen - specific immunoassays detect IgE antibody in the serum of most but not all patients who respond clinically to those allergens.  The National Asthma Education Program Expert Panel Report (2007) recommends the use of skin testing or in vitro IgE antibody testing to determine the presence of specific IgE antibodies to the allergens to which the patient is exposed.  The Expert Panel concluded that allergy skin or in vitro IgE antibody tests are reliable in determining the presence of specific IgE.  The Expert Panel Report stated that either skin tests or in vitro IgE antibody tests can be used to assess specific IgE sensitization to Aspergillus in persons suspected of having allergic bronchopulmonary aspergillosis.

   3. According to the National Asthma Education and Prevention Program Guidelines for the Diagnosis and Management of Asthma, advantages of RAST and other in vitro tests over skin tests include the fact that they do not require knowledge of skin testing technique, they do not require availability of allergen extracts, they can be performed on patients who are taking medications that suppress the immediate skin test (e.g., antihistamines, antidepressants), they carry no risk of systemic reactions, and they can be done on patients with extensive eczema.  Despite the advantages, there are 2 major concerns limiting the use of in-vitro tests for allergen-specific IgE in the United States.  The first limitation is the rather consistent finding that in-vitro tests are not as sensitive as skin tests for detecting allergen-specific IgE.  The second limitation is that on a per test basis skin tests have lower time and reagent costs.  Other advantages of skin tests are that they are faster (results are available within an hour), and the results are visible to the patient (this may enhance patient compliance).

      A variety of modifications have been made to tests related to RAST (such as MAST, PRIST, RIST, FAST, MRT, VAST, ELISA, and ImmunoCAP).

      ImmunoCAP (Pharmacia Diagnostics, Clayton, N.C.) is an in vitro-specific immunoglobulin E test that uses a three-dimensional cellulose solid allergen phase; by contrast, the older modified Phadezym-Rast (Pharmacia Diagnostics) uses a 2-dimensional solid phase.  The ImmunoCAP provides more rapid results (available in 6 hours) compared to traditional RAST tests (Phadezym-RAST results take 3 days to obtain).  With the ImmunoCAP, solid-phase bound allergens are allowed to react with IgE antibodies in the sample; the IgE antibodies are detected by labeled anti-IgE.  To minimize handling and increase safety, the system includes instrumentation and computer software that handles the technical manipulations, the measurements and the data management.  The assay is calibrated against the WHO standard for IgE and includes 2 sets of calibrators, 1 for specific IgE Ab and low-range total IgE, and the other for wide-range total IgE.  Results from published studies report the overall sensitivity and specificity of different allergens compared to expert clinical diagnosis range from 78 to 94 % and 77 to 94 %, respectively.

      Total Serum IgE

      An elevated serum IgE level is one of the diagnostic criteria of allergic bronchopulmonary aspergillosis (ABPA).  IgE levels can be used to follow the course of the disease.  Serum IgE levels will fall when the disease is successfully treated with corticosteroids; rising IgE levels indicate disease exacerbations.

      Total serum level of IgE is correlated with allergic disease in only a general way.  Elevated levels are associated with the presence of allergy, while normal levels are not. However there are many individuals with clinical symptoms and allergen-specific IgE who have serum IgE levels within the normal range.  Because of this, routine measurement of serum IgE is not a useful screening test for allergy.

      IgG RAST/ELISA Testing

      There is no evidence that IgG antibodies are responsible for delayed allergic symptoms or intolerance to foods. In their Choosing Wisely Campaign, the American Academy of Allergy, Asthma and Immunology recommends against immunoglobulin G (IgG) testing in the evaluation of allergy. The AAAAI states that appropriate diagnosis and treatment of allergies requires specific IgE testing (either skin or blood tests) based on the patient’s clinical history.

      ALCAT

      ALCAT food allergy testing utilizes an indirect method of measuring mediator releases and the effects of other pathogenic mechanisms of allergy and delayed hypersensitivity.  It employs semi-automated Coulter Electronics and fully automated computer analysis.  This automated testing has not been validated and has not been established as a useful allergy test in clinical practice.

      Cytotoxic Testing (Bryans Test)

      Cytotoxic testing is based on the theory that the addition of a specific allergen to either whole blood or a serum leukocyte suspension from a suspected allergic patient will result in reduction of the white blood cell count or death of the leukocytes, thereby indicating the presence of an immune response.  Controlled studies have failed to substantiate the value of cytotoxic testing for the diagnosis of allergies, whether they are airborne, foods, or chemicals.

      ELISA/ACT

      ELISA/ACT tests lymphocytes in a laboratory culture for their reaction to up to 300 purified foods, preservatives, chemicals and minerals.  This test is not FDA approved and is not established as a useful test in clinical practice.

      Food Immune Complex Assays (FICA)

      FICA are based on the standard solid phase radioimmunoassay methodology.  These assays have not yet been subjected to rigorous study of potential false-negative and false-positive results.  Clinical studies to date indicate that circulating immune complexes can be found in a normal population of people having no food allergy.  The value of the measurement of FICA toward the diagnosis of food allergy remains unproven and does not have a place in current clinical practice.

      Rebuck Skin Window Test

      Rebuck skin window test is an immunologic test in which the skin is abraded with a scalpel.  Laboratory cover slips are placed over the abraded areas for 24 hours.  The cover slips are then stained and analyzed.  An immune deficiency may be present if there is an abnormality of monocytes displayed either by their absence or their inability to migrate to intracellular sites of antigen within 12 hours.  This test is not useful in documenting allergies since other immunodeficiencies can be found in patients with allergic conditions.

      Leukocyte Histamine Release Test

      The leukocyte histamine release test is a measurement of the amount of histamine released in-vitro.  Varying concentrations of an allergen extract are added to the patient's peripheral blood leukocytes.  Histamine is normally released as a consequence of the interaction of allergen with cell-bound IgE antibodies.  If an individual is atopic to a specific antigen, the leukocytes will not release the histamine in-vitro.  Only a limited number of allergens can be tested from a single aliquot of blood and quality control studies have shown considerable variability in the measurement of histamine results.

      Mediator Release Test

      The mediator release test (MRT) (Signet Diagnostic Corporation) has primarily been used to detect intolerance to foods and additives in patients with irritable bowel syndrome.  The MRT measures the aggregate release of inflammatory mediators from the patient's immunocytes in vitro after exposure to specific foods and food additives.  The results of the mediator release test have been used to design a patient-specific diet to treat IBS by avoiding foods and additives that trigger significant inflammatory mediator release.  For the mediator release test, the patient's blood sample is incubated with various extracts of foods and food additives and then analyzed for the presence and aggregate amount of release of inflammatory mediators from the patient's leukocytes.  Results are compared to control samples of the patient's blood that have not been exposed to food extracts or additives.  The MRT-directed patient-specific diet is one component of the Lifestyle Eating and Performance (LEAP) Disease Management Program (Don Self & Associates, Inc., Whitehouse, TX).  The LEAP program is based on the theory that symptoms irritable bowel syndrome and other certain conditions are caused by the physiological effects of non-IgE mediated immune reactions in response to sensitivities to specific foods and food additives.  The LEAP program also includes patient selection tools, a self-directed stress reduction program, and outcomes assessment tools.  According to the manufacturer, the LEAP program has been successful in reducing or eliminating symptoms in 84 % of patients with irritable bowel syndrome, functional diarrhea, and related conditions.  However, there is no evidence in the peer-reviewed published medical literature to substantiate these claims.

      The mediator release test has also been promoted for use in patients with chronic fatigue syndrome, metabolic conditions (e.g., diabetes, obesity), gastrointestinal disorders (e.g., gastroesophageal reflux disease, chronic ulcerative colitis, and Crohn's disease), neurologic disorders (e.g., migraine headaches, cluster headaches), rheumatologic disorders (inflammatory arthritis, arthralgias, fibromyalgia), otolaryngologic disorders (e.g., perennial rhinitis, chronic sinusitis, chronic otitis media with effusion), dermatologic conditions (e.g., eczema, urticaria, dermatitis), and in patients with behavioral conditions (e.g., attention deficit disorder, hyperactivity, frequent mood swings, inability to concentrate).  There are, however, no studies of the mediator release test reported in the peer-reviewed published medical literature that demonstrate improvements in clinical outcomes by incorporating the mediator release test and associated dietary modifications into the clinical management of patients with these conditions.  Thus, the mediator release test is considered experimental and investigational.

      Eosinophil Cationic Protein

      Eosinophil cationic protein (ECP) is an eosinophil-specific mediator that can be measured in bodily fluids to estimate the extent of eosinophil activation, although it provides no information about the presence of IgE-mediated allergy.  This test requires further characterization before it can be recommended for routine clinical use.

      Anti-IgE and Anti-Fc Epsilon Receptor Antibodies

      Anti-Fc epsilon receptor antibodies are natural antibodies against the alpha chain of the high-affinity receptor for IgE.  Guidelines on urticaria from the British Association of Dermatologists (Grattan et al, 2007) stated that the presence of anti-Fc epsilon receptor antibodies indicates an autoimmune urticaria, but make no recommendation for testing for anti-Fc epsilon antibody in the work-up of patients with urticaria.  Saini (2010) stated that tests used in investigations of pathogenesis of chronic urticaria include the autologous serum and plasma skin tests, assays for autoantibodies directed against IgE or the FcepsilonRI receptor, and in vitro assessments of basophil function.  However, these tests lack specificity and prognostic value for chronic urticaria, are not standardized, and can not be recommended for routine clinical use.  

      Clifford Materials Reactivity Testing

      According to Clifford Consulting Research Laboratories, Clifford materials reactivity testing (CMRT) is a laboratory screening process used to help identify sensitivity to various chemicals and compounds used in dental, orthopedic, or surgical implants, in order to select a product to which the patient exhibits the least sensitivity.  The laboratory states that they report on more than 11,300 trade-named dental products and 94 chemical groups and families.  They state that they have also added an Orthopedic panel reporting on over 4,000 trade-named products for surgical applications.  However, there is a lack of peer-reviewed published evidence of the clinical effectiveness of CMRT.  http://www.ccrlab.com/

      Allergy Immunotherapy
      
      The treatment of allergy is approached 3 ways: (i) avoidance therapy, (ii) pharmacologic therapy, and (iii) immunotherapy.  Complete avoidance of the known allergen responsible for inducing the signs and symptoms of the allergy is the most effective treatment for any allergic condition and results in a cure.  When avoidance of a specific allergen such as house dust, molds or pollens is impossible, pharmacologic therapy is used (e.g., antihistamines, adrenergic agonists, anticholinergics, beta-adrenergic agonists, corticosteroids, cromolyn sodium and methylxanthines).  It has been advocated that the utilization of air cleaners, humidifiers, or dehumidifiers is helpful in reducing allergic irritant substances in the environment; however, research indicates that the use of these mechanical devices was ineffective in reducing clinical symptoms.
      
      Allergy immunotherapy (also known as desensitization, hyposensitization, allergy injection therapy, or "allergy shots"), is indicated in patients whose triggering allergens are not readily avoidable, the allergy is IgE-mediated as documented by skin testing or RAST, the symptoms are not easily controlled with medication, the symptoms encompass more than one season and the patients are likely to cooperate in the program.  The severity, duration and frequency of episodes should be explored.  Patients with life-threatening allergy (severe anaphylactic reaction) to hymenoptera (venom from bees, hornets, wasps or fire ants) have been shown to respond well to allergy immunotherapy, as well as patients with severe seasonal allergic rhinitis or conjunctivitis, perennial allergic rhinitis, allergic (extrinsic) asthma and mold induced allergic rhinitis.  Allergy immunotherapy will help desensitize the patient to the effects of the allergen.  The documented allergy should correspond to the allergen planned for immunotherapy.  A trial of systemic medications or avoidance of the allergens should be attempted.  Two or more medications (antihistamines, steroids, bronchodilators, intranasal cromolyn) if not contraindicated should have been prescribed during the past year or the patient should be currently receiving immunotherapy.
      
      Allergy immunotherapy is defined as the repeated administration of specific allergens to patients with IgE-mediated conditions, for the purpose of providing protection against the allergic symptoms and inflammatory reactions associated with natural exposure to these allergens.  The exact mechanism of action is not known but may involve an increase in allergen-specific IgG antibodies, a decrease in IgE synthesis, and alteration in T-lymphocyte activity.  The principal and most effective route of allergen application is by subcutaneous injection.  Oral/sublingual application of allergen extracts is discussed controversially in the literature (see provocation-neutralization therapy).  There is a great assortment of different allergen extracts available, but only standardized extracts should be used. In the United States, the Food and Drug Administration (FDA) determined that the intracutaneous technique should be used for assigning standardized unitage (i.e., bioequivalency allergy units [BAU]).  Patients with allergic rhinitis and/or asthma from tree and grass pollens in the spring, ragweed pollen in the fall and year-round dust-mite sensitivity who have had inadequate response to acceptable symptomatic medication and allergen avoidance are excellent candidates for immunotherapy.  Immunotherapy is recommended for patients with allergic asthma unresponsive to allergen avoidance, even when symptomatic relief can be achieved with drug therapy.  Treatment plans vary, but generally follow an initial dosing of short intervals (2 to 7 days) and should be increased 1.5 to 2 times with each injection if no reaction occurs.  This dosing is followed by a maintenance dosage regimen at 3- or 4-week intervals and is determined by patient tolerance and relief of symptoms.  Length of therapy varies from 3 to 5 years.  The progress of the patient should be reviewed at regular intervals by the physician.  Progressive improvement may be observed over the first 2 to 3 years of treatment.  Discontinuation of therapy may be considered any time after a 2 to 3 year trial.  The risk of relapse must be weighed against patient preference for continuation of therapy.  Examples of potential allergens for which immunotherapy is effective include: animal dander, animal feathers, animal fur, dust, grasses, insects, mites, molds, mushrooms, orris root, plants, pyrethrum, seeds, trees, vegetable gums, weeds, hymenoptera or stinging insects (bees, hornets, wasps, fire ants).
      
      There is no evidence that immunotherapy is beneficial for food allergy, migraine headaches, vasomotor rhinitis, intrinsic (non-allergic) asthma, or chronic urticaria.  In addition, there is little evidence that immunotherapy benefits atopic dermatitis and angioedema.  The major risk factor of allergy immunotherapy is anaphylaxis. Immunotherapy should be administered under the supervision of an appropriately trained physician who can recognize early signs and symptoms of anaphylaxis and administer emergency medications if needed.
      
      A structured evidence-based assessment of sublingual immunotherapy for adults conducted by the BlueCross BlueShield Association Technology Evaluation Center (2003) concluded that “[w]hether [sublingual immunotherapy] improves health outcomes when compared with injection [allergen-specific immunotherapy] has not yet been demonstrated in the investigational setting.  It is uncertain whether FDA-licensed allergen preparations manufactured for allergy testing and injection [allergen-specific immunotherapy] are suitable for sublingual administration.  Based on the above, use of sublingual immunotherapy for patients with allergies does not meet the TEC criteria.” 
      
      Cox and colleagues (2006) stated that sublingual immunotherapy (SLIT) has been utilized with increasing frequency in Europe and is viewed with increasing interest by allergists in the United States.  To address this interest, a Joint Task Force of the American College of Allergy, Asthma and Immunology and the American Academy of Allergy, Asthma and Immunology's Immunotherapy and Allergy Diagnostic Committees evaluated the evidence on the effectiveness of SLIT.  The task force concluded that despite clear evidence that SLIT is an effective treatment, there are still many unanswered questions, including effective dosage, treatment schedules, and overall duration of treatment.  Until these questions have been answered, an assessment of the cost/benefit ratio of the treatment cannot be made.  Sublingual immunotherapy does seem to be associated with few severe side effects, but it has not been used in high-risk asthmatic patients, nor in the studies reviewed has it been used as a mixture of non-cross-reacting allergens.  Furthermore, there is currently no allergy extract approved for this use in the United States, nor is there a Current Procedural Terminology code for billing purposes.  All of these factors should be considered before contemplating initiation of SLIT treatment for allergic patients.  
      
      Nelson (2009) reviewed the literature on allergen immunotherapy for studies simultaneously using 2 or more distinct allergen extracts in either subcutaneous or sublingual immunotherapy.  A total of 13 studies were identified, subcutaneous injections (n = 11), sublingual administration (n = 1), and both (n = 1).  In studies with adequate information, administration of 2 extracts by means of either subcutaneous immunotherapy or sublingual immunotherapy was effective.  In studies using multiple allergens, 3 studies showed clear efficacy, whereas in the other 2 studies, lack of efficacy might have been due to inadequate doses of extract or omission of clinically relevant allergens in the treatment regimen.  The author concluded that simultaneous administration of more than 1 allergen extract is clinically effective.  However, more studies are needed, particularly with more than 2 allergen extracts and with sublingual administration.
      
      Hoeks et al (2008) examined the evidence of the safety and effectiveness of SLIT as a curative therapy for allergies in children.  All randomized, double-blind and placebo-controlled studies (DBRPCT's) on SLIT in asthma or rhinoconjunctivitis in children were selected from Medline, Embase and Cochrane Central Register of Controlled Trials.  Also references of the found articles were used.  The selected studies were assessed for quality and the different outcomes were evaluated.  A total of 13 DBRPCT's on SLIT in children were selected, 5 studies on children with house dust mite allergy and 8 studies on children with grass pollen allergy.  There was considerable heterogeneity among the different studies with respect to the choice and definition of outcome criteria.  The quality of the included studies was moderate.  After treatment with SLIT, especially reported symptoms decreased without improvement of objective parameters.  Positive results originated especially from significant differences within the intervention group before and after treatment.  These investigators concluded that it was impossible to substantiate the claim of authors of the studies regarding the favorable effects of SLIT in children with asthma or rhinoconjunctivitis, since all studies had serious methodological flaws.  However, the studies showed that SLIT seems to be safe in children in the doses applied.  This is in agreement with the findings of Roder et al (2008) who reported that there is currently insufficient evidence that immunotherapy in any administration form has a positive effect on symptoms and/or medication use in children and adolescents with allergic rhinoconjunctivitis.
      
      In a randomized, double-blind, placebo-controlled study, Severino et al (2008) evaluated if SLIT might potentially be beneficial in hymenoptera (honeybee)allergy.  The sting challenge in large local reactions (LLRs) was used to test this hypothesis.  After the baseline sting challenge, subjects were randomized to either SLIT or placebo for 6 months.  The treatment involved a 6-week build-up period, followed by maintenance with 525 microg of venom monthly.  The sting challenge was repeated after 6 months.  A total of 30 patients (18 males; mean age of 44.5 years) were enrolled, and 26 completed the study, with 1 dropout in the active group and 3 dropouts in the placebo group.  In the active group the median of the peak maximal diameter of the LLRs decreased from 20.5 to 8.5 cm (p = 0.014), whereas no change was seen in the placebo group (23.0 versus 20.5 cm, p = not significant).  The diameter was reduced more than 50 % in 57 % of patients.  One case of generalized urticaria occurred in a placebo-treated patient at sting challenge.  No adverse event caused by SLIT was reported.  The authors concluded that honeybee SLIT significantly reduced the extent of LLRs, and its safety profile was good.  Although LLRs are not an indication for immunotherapy, this proof-of-concept study suggested that SLIT in hymenoptera allergy deserves further investigation.  Trials involving systemic reactions and dose-ranging studies are needed. 
      
      Skoner and colleagues (2010) examined the maintenance dose range of sublingual standardized glycerinated short ragweed pollen extract in adults with ragweed-induced rhinoconjunctivitis.  A  total of 115 patients with ragweed-induced rhino-conjunctivitis were randomly allocated to placebo (n = 40), medium-dose extract (4.8 microg Amb a 1/d; n = 39), or high-dose extract (48 microg Amb a 1/d; n = 36).  In a 1-day (rush) dose-escalation regimen, ragweed pollen extract was administered sublingually in incremental doses until maximum tolerable or scheduled dose was reached and then maintained during the ragweed pollen season.  Patient diaries were used to monitor nasal and ocular symptoms and medication.  The primary endpoint was symptom score.  Both active treatment groups achieved a 15 % reduction in total rhino-conjunctivitis symptom scores compared with placebo during the entire ragweed pollen season, but the difference was not statistically significant (p > 0.10).  However, in an analysis of co-variance correcting for pre-seasonal symptoms, both mean daily symptom scores (0.19 +/- 1.16 versus 1.00 +/- 2.30) and medication scores (0.0003 +/- 1.64 versus 0.63 +/- 1.06) for the entire pollen season were significantly reduced in the high-dose versus placebo groups, respectively (p < or = 0.05).  Ragweed-specific IgG, IgG(4), and IgA antibodies were increased after treatment in the medium- and high-dose groups and not the placebo group.  Frequency of adverse events was similar between the placebo and treatment groups, but oral-mucosal adverse events occurred more often with treatment.  The authors concluded that standardized glycerinated short ragweed pollen extract administered sublingually at maintenance doses of 4.8 to 48 microg Amb a 1/d was safe and can induce favorable clinical and immunologic changes in ragweed-sensitive subjects. However, the authors noted that additional trials are needed to establish efficacy.
      
      Sieber et al (2010) compared the effectiveness of perennial and co-seasonal high-dose SLIT treatments as well as ultra-rush and classical titrations in a real-world setting for pollen allergens.  An individual patient data (IPD) meta-analysis was performed of 3 open, prospective observational studies on high-dose SLIT using IR-standardized allergen extracts in patients with allergic rhinitis with and without asthma.  A total of 1,052 patients aged 24.9 years (mean) were treated with SLIT and included in this IPD meta-analysis.  Individual studies and total data pool analyses revealed consistent improvements in rhino-conjunctivitis symptom scores.  Stratified analyses revealed consistent improvements in symptomatic score and medication score regardless of the type of sensitization and type of treatment.  Ultra-rush titration resulted in considerably more pronounced improvement in symptom scores than classical titration, possibly due to better compliance of patients receiving that supervised titration.  Adverse events occurred in 24 % of patients during titration and in 18 % of patients during maintenance treatment.  The vast majority of events (89 % and 87 %) were mild-to-moderate, predominantly local symptoms in the oral cavity.  There were no differences detected between the study titration or treatment schedules.  No serious adverse reactions were reported.  Nearly all patients (88 %) decided to continue SLIT after completion of the studies.  High-dose SLIT with seasonal allergens given as co-seasonal or perennial treatment appears to be effective and well-tolerated in daily medical practice.  Improved compliance under ultra-rush titration and seasonal SLIT treatment may further enhance effectiveness.  The authors stated that randomized controlled trials are needed for the further evaluation of these findings.

      The National Institute of Allergy and Infectious Diseases' guidelines for the diagnosis and management of food allergy (Boyce et al, 2010) stated that (i) the expert panel does not recommend using allergen-specific immunotherapy to treat IgE-mediated food allergy (Rationale: Allergen-specific immunotherapy improves clinical symptoms of FA while on treatment.  However, it is currently difficult to draw conclusions on the safety of such an approach and whether clinical tolerance [i.e., improvement in clinical symptoms that persists even after allergen-specific immunotherapy is discontinued] will develop with long-term treatment).  Allergen-specific immunotherapy can improve clinical symptoms of food allergy for some patients.  However, additional safety and efficacy data are needed before such treatment can be recommended.  Because of the risk of severe reactions, the approach should only be used in highly controlled settings, and (ii) the expert panel does not recommend immunotherapy with cross-reactive allergens for treating IgE-mediated food allergy (Rationale: Although some evidence exists to suggest that specific immunotherapy with cross-reactive allergens is beneficial in treating food allergy, additional safety and efficacy data are needed before such treatment can be recommended).  It has been hypothesized that immunotherapy with cross-reactive antigens could benefit patients with food allergy, yet the safety of this approach has been evaluated in a highly controlled setting in only 1 study to date.  Replication of these findings with additional safety and efficacy data in clinical practice settings is needed.

      de Bot et al (2011) evaluated the quality of systematic reviews and meta-analyses of SLIT for allergic rhinitis in children, published since 2000.  Eligible reviews were identified by searching Medline/PubMed, Embase, and the Cochrane Library, from 2000 through 2008.  Methodological quality was assessed using the assessment of multiple systematic reviews instrument.  A total of 10 systematic reviews were included, 1 of which was published in the Cochrane Library.  Eight reviews gave some details about the search strategy.  None of the reviews included measures to avoid selection bias.  In 60 % of the reviews, the methodological quality of the included studies was (partly) assessed.  Four reviews pooled the results of individual studies, neglecting clinical heterogeneity.  Three of the 10 reviews provided information about sources of funding or grants from industry.  Of the 10 reviews, the 6 reviews with the highest overall score scored 5 to 8 points, indicating moderate quality.  The authors concluded that systematic reviews are useful to evaluate the efficacy of SLIT in children.  Although more reviews have become available, the methodological quality could be improved. 

      They stated that SLIT for children could be promising, but methodological flaws in the reviews and individual studies are too serious to draw definite conclusions.

      In a Cochrane review, Calderon et al (2011) evaluated the effectiveness of SLIT compared with placebo for reductions in ocular symptoms, topical ocular medication requirements and conjunctival immediate allergen sensitivity.  These investigators searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2011, Issue 1), MEDLINE (January 1950 to January 2011), EMBASE (January 1980 to January 2011), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to January 2011), Web of Science (January 1970 to January 2011), Biosis Previews, (January 1979 to January 2011), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com) (January 2011), ClinicalTrials.gov (www.clinicaltrials.gov) (January 2011), the Australian New Zealand Clinical Trials Registry (ANZCTR) (www.actr.org.au) (July 2010), SCOPUS (November 2008) and the UK Clinical Trials Gateway (January 2010).  There were no language or date restrictions in the search for trials.  All electronic databases except for SCOPUS, the UK Clinical Trials Gateway and ANZCTR were last searched on 19 January 2011.  Randomized controlled trials (RCTs), double-masked and placebo controlled, which evaluated the efficacy of SLIT in patients with symptoms of allergic rhino-conjunctivitis (ARC) or allergic conjunctivitis (AC) were included in this analysis.  The primary outcome was the total ocular symptom scores.  Secondary endpoints included individual ocular symptom scores (such as itchy eyes, red eyes, watery eyes, swollen eyes), ocular medication scores (eye drops) and conjunctival immediate allergen sensitivity (CIAS).  Data were analyzed and reported as standardized mean differences (SMDs) using Review Manager software.  A total of 42 trials (n = 3,958 total participants; n = 2,011 SLIT and n = 1,947 placebo) had available data to evaluate the efficacy of SLIT on AC and were included in the meta-analyses.  Heterogeneity among studies (I(2) statistic) was around 50 % or below for all endpoints.  Sublingual immunotherapy induced a significant reduction in both total ocular symptom scores (SMD -0.41; 95 % confidence interval [CI]: -0.53 to -0.28; p < 0.00001; I(2) = 59%) and individual ocular symptom scores for red eyes (SMD -0.33; 95 % CI: -0.45 to -0.22; p < 0.00001; I(2) = 27 %), itchy eyes (SMD -0.31; 95 % CI: -0.42 to -0.20; p < 0.00001; I(2) = 46 %) and watery eyes (SMD -0.23; 95 % CI: -0.34 to -0.11; p < 0.0001; I(2) = 42 %) compared to placebo.  Those participants having active treatment showed an increase in the threshold dose for the conjunctival allergen provocation test (SMD 0.35; 95 % CI: 0.00 to 0.69; p = 0.05; I(2) = 43 %).  No significant reduction was observed in ocular eye drops use (SMD -0.10; 95 % CI: -0.22 to 0.03; p = 0.13; I(2) = 34 %).  The authors concluded that overall, SLIT is moderately effective in reducing total and individual ocular symptom scores in participants with ARC and AC.  There were however some concerns about the overall quality of the evidence-base, this relating to inadequate descriptions of allocation concealment in some studies, statistical heterogeneity and the possibility of publication bias.  They stated that there is a need for further large rigorously designed studies that examine long-term effectiveness after discontinuation of treatment and establish the cost-effectiveness of SLIT.
      
      Allergoids 
      
      Allergoids are formalin treated allergens which have been shown to be as effective as conventional aqueous extracts and superior to placebo in terms of reduction of symptom medication scores, production of an increase in ragweed IgG levels, and a decrease in seasonal rise in ragweed IgE levels.  Allergoids are licensed and manufactured for general distribution in Europe, but not yet in the United States.
      
      Enzyme Potentiated Desensitization (EPD)
      
      Enzyme potentiated desensitization is patented in Europe under the brand name of Epidyme.  This immunotherapy consists of a mixture of allergens to molds, grass, weeds, trees, dust mites, dog and cat dander, and house dust.  These allergens are administered in the doctor's office.  While this is common practice in Europe, it is not on the United States market or regulated/approved by the U.S. FDA.  The FDA has banned importation of EPD.  There is a lack of clinical trials supporting the efficacy of this product.
      
      A variant of enzyme potentiated desensitization is ultra low dose enzyme activated immunotherapy (also known as low dose allergens or LDA), which has been described as a method of immunotherapy enhanced by a minute dose of the enzyme, beta glucuronidase.  According to proponents, the beta glucuronidase activates extremely miniscule doses of various allergens and stimulates the production of T-suppressor cells.  The T-suppressor cells, in turn, down regulate the T-helper cells that are causing allergic symptoms by misidentifying normal substances in the body as allergens.  LDA uses the same active components as EPD, but utilizes more more pollens, foods and other allergens.
      
      Photo-Inactivation
      
      Photo-inactivation of an antigen with ultraviolet may allow larger doses of antigen to be administered with fewer adverse effects.  Currently, these preparations are used for research purposes only and not in clinical practice.
      
      Polymerized Ragweed Extract
      
      Polymerized ragweed extract has been employed for treatment of ragweed hay fever in placebo-controlled trials and has been shown to produce a significant decrease in symptoms and medication scores.  However, polymerized ragweed extracts have not yet been licensed or manufactured for general distribution in the United States.
      
      Rhinophototherapy
      
      Phototherapy has a profound immunosuppressive effect and is able to inhibit hypersensitive reactions in the skin.  Leimgruber (2006) stated that phototherapy applied inside the nose (rhinophototherapy) is among new therapeutic options being developed for allergic rhinitis to counteract its impact on quality of life and health costs.  The author noted that the immunosuppressive effect of phototherapy has been tested in nasal mucosa.  This application has shown anti-inflammatory results in nasal cleaning fluid and, consequently, may reduce allergic rhinitis.  The author noted that long-term studies involving large cohorts of patients are needed if rhinophototherapy is going to be prescribed without restrictions.
      
      In a randomized, double-blind study (n = 49), Koreck et al (2005) examined if phototherapy using a combination of UVB (5 %), UVA (25 %), and visible light (70 %), referred to as mUV/VIS (rhinophototherapy), is effective in treating allergic rhinitis.  The study was carried out during the ragweed season.  Each intra-nasal cavity was illuminated 3 times a week for 3 weeks with mUV/VIS or with low-intensity visible light (control group).  Symptom scores, inflammatory cells, and their mediators were assessed in nasal lavages.  In vitro effects of mUV/VIS irradiation on T-cell and eosinophil apoptosis, and its inhibitory effect on mediator release from basophils were examined.  Rhinophototherapy was well-tolerated, and resulted in a significant improvement of clinical symptoms for sneezing (p < 0.016), rhinorrhea (p < 0.007), nasal itching (p < 0.014), and total nasal score (p < 0.004).  None of the scores improved significantly in the control group.  The investigators reported that scores for nasal obstruction slightly improved after rhinophototherapy and significantly increased in the control group (p < 0.017).  In the nasal lavage, rhinophototherapy significantly reduced the number of eosinophils and the level of eosinophil cationic protein and IL-5.  In vitro irradiation of T-cells and eosinophils with rhinophototherapy dose-dependently induced apoptosis.  In addition, rhinophototherapy inhibited the mediator release from RBL-2H3 basophils.  These promising results would need to be replicated in a larger clinical trial with longer-term follow-up. 
      
      The Helminth Trichuris Suis Therapy
      
      In a double-blind, placebo-controlled, parallel group study, Bager et al (2010) ascertained the effectiveness of helminth Trichuris suis therapy for the treatment of allergic rhinitis.  A total of 100 subjects aged 18 to 65 years with grass pollen-induced allergic rhinitis were randomly assigned to ingest a total of 8 doses with 2,500 live Trichuris suis ova or placebo with an interval of 21 days.  The primary outcome was a change in mean daily total symptom score for runny, itchy, sneezing nose (maximum change, 9.0) or in percentage of well days during the grass pollen season.  Treatment with Trichuris suis ova (n = 49) compared with placebo (n = 47) caused transient diarrhea peaking at day 41 in 33 % of participants (placebo, 2 %), and increased eosinophil counts (p < 0.001) and Trichuris suis-specific IgE (p < 0.05), IgG (p < 0.001), IgG(4) (p < 0.003), and IgA (p < 0.001), whereas there was no significant change in symptom scores (0.0; 95 % confidence interval [CI]: -0.5 to 0.4; p = 0.87), well days (3 %; 95 % CI: -9 % to 14 %; p = 0.63), total histamine (p = 0.44), grass-specific IgE (p = 0.76), or diameter of wheal reaction on skin prick testing with grass (p = 0.85) or 9 other allergens.  The authors concluded that repeated treatment with the helminth Trichuris suis induced a substantial clinical and immunologic response as evidence of infection, but had no therapeutic effect on allergic rhinitis.

2. Urine Auto-Injection
   
   The practice of injection of an extract of the patient's own urine for diagnosis and treatment of allergy is clearly unacceptable and must be discouraged.  It is not based on rational theory, and there have been no scientific investigations of efficacy and safety.  There is a potential danger for autoimmune nephritis with this procedure.

3. Multiple Chemical Sensitivity Syndrome
   
   Multiple chemical sensitivity (MCS) (also known as idiopathic environmental intolerance (IEI), clinical ecological illness, clinical ecology, environmental illness, chemical AIDS, environmental/chemical hypersensitivity disease, total allergy syndrome, cerebral allergy, 20th century disease) has been used to describe a condition whereby an individual becomes chronically ill from exposure to chemicals in foods and the environment at doses far below the levels normally considered safe.  Resulting “allergies” to these chemicals have been postulated to cause a number of troubling symptoms (e.g., fatigue, irritability, behavior problems, depression, confusion, and nervous tension in children) in the absence of objective physical findings.  The existence of such a syndrome has been based on anecdotal reports and uncontrolled studies.  Several well-designed investigations suggest that most people diagnosed with MCS have a medical or psychosomatic disorder that they can not accept, preferring instead to interpret their symptoms as environmental sensitivities.  If this is true, the diagnosis of MCS may delay proper medical and psychiatric care.
   
   The theories and practices involving environmental allergies of this type have been severely criticized by the American Medical Association, the American College of Physicians, the Canadian Psychiatric Association, the International Society of Regulatory Toxicology and Pharmacology, the American Academy of Allergy, Asthma and Immunology (AAAAI), and several scientific panels that have investigated them.  Based on the reports in the peer-reviewed scientific literature, the American Medical Association's Council on Scientific Affairs stated that “there are no well controlled studies establishing a clear mechanism or cause for multiple chemical sensitivity syndrome.”  Recently (January 1999), the AAAAI reviewed the evidence again and concluded, “Rigorously controlled studies to verify the patient's reported subjective sensitivity to specific environmental chemicals have yet to be done.  Moreover, there is no evidence that these patients have any immunologic or neurologic abnormalities.  In addition, no form of therapy has yet been shown to alter the patient's illness in a favorable way.”
   
   Confinement in an environmental control unit or facility (ecology unit), which has been used as a treatment for environmental illnesses and hypersensitivities, has not been established as an effective or appropriate treatment.

4. Electromagnetic Sensitivity Syndrome

   A number of people who suffer from non-specific health symptoms (e.g., allergies, headache, fatigue, skin symptoms, anginal-like complaints, difficulties in concentrating, mood and sleep disturbances) have claimed that they are sensitive to electromagnetic waves and electromagnetic pollution from antennas, cell phones, computers, electrical appliances, video display units, and overhead power lines, etc.  The term "electromagnetic sensitivity (also known as allergy to electricity, electro-sensitivity, electrohypersensitivity, and hypersensitivity to electricity) has been used to describe these individuals.  However, it is not an established disease.  There is no reliable clinical data to support the theory that low level electromagnetic waves cause these symptoms.  There are no accepted diagnostic criteria or procedures for the diagnosis and treatment of electromagnetic sensitivity.  Furthermore, no direct cause-effect relationship between electromagnetic sensitivity symptoms and electromagnetic fields has been proven.

   A number of controlled studies have found no effect of exposure to electromagnetic fields on symptoms or signs. Lonne-Rahm et al (2000) studied the effects of provocation with stress and electricity of patients with "sensitivity to electricity".  A total of 24 patients with self-reported "sensitivity to electricity" were divided into 2 groups and tested in a double-blind provocation study.  These patients, who reported increased skin symptoms when exposed to electromagnetic fields, were compared with 12 age- and sex-matched controls.  Both groups were exposed to 30-min periods of high or low stress situations, with and without simultaneous exposure to electromagnetic fields from a visual display unit.  The matched controls were tested twice and given the same exposure as the patients, but had the fields turned on every time.  Stress was induced by requiring the participants to act in accordance with a random sequence of flashing lights while simultaneously solving complicated mathematical problems.  Blood samples were analyzed for levels of the stress-related hormones melatonin, prolactin, adrenocorticotrophic hormone, neuropeptide Y, and growth hormone, and the expression of different peptides, cellular markers, and cytokines (CD1, factor XIIIa, somatostatin, and tumor necrosis factor-alpha).  Skin biopsies were also analyzed for the occurrence of mast cells.  Stress provocation resulted in feelings of more intense mental stress and elevated heart rate.  The patients reported increased skin symptoms when they knew or believed that the electromagnetic field was turned on.  With the blind conditions, there were no differences between "on" or "off".  Inflammatory mediators and mast cells in the skin were not affected by the stress exposure or by exposure to electromagnetic fields.  The authors concluded that the patients did not react to the fields.

   Flodin et al (2000) performed a provocation study in the homes or workplaces of patients with electric hypersensitivity; they also studied the symptoms and on-off answer 24 hours after the exposure.  A total of 15 subjects selected as having fast and distinct reactions from electric equipment were provoked on 4 occasions: mainly 2 true and 2 sham provocations.  The intervals between exposure were a few or more days in order to provide the subjects with an opportunity to recover before the next provocation.  A control group of healthy subjects with normal hearing and vision verified that the provocations were performed in a blind manner.  Patients suffering from "electric hypersensitivity" were no better than the control group in deciding whether or not they were exposed to electric and magnetic fields.  The authors concluded that exposure to electric and magnetic fields per se does not seem to be a sufficient cause of the symptoms experienced by this patient group.

   Lyskov et al (2001) examined possible neurophysiological effects of intermittent 15 sec on/off cycle, 60 Hz, 10 microT magnetic field exposure on patients with perceived "electromagnetic hypersensitivity" (EHS), and control subjects during rest and performance of a mental arithmetic task.  A total of 20 participants (15 females, 5 males, 31 to 60 years old, mean of 45.8 +/- 0.7 years) were invited from the group of EHS patients.  Twenty volunteers (15 females, 5 males, 31 to 59 years old, mean of 45.0 +/- 0.7 years) served as a control group.  The test protocol consisted of a set of examinations: EEG, visual evoked potentials, electrodermal activity, ECG, and blood pressure.  The total duration of the test was 40 mins, divided into 2 10-min rest periods and 2 10-min periods of mathematical performance.  Magnetic field and sham exposures were presented randomly during these periods, resulting in 4 different conditions: (i) Field-Rest, (ii) Sham-Rest, (iii) Field-Math, and (iv) Sham-Math.  The data showed significant main effects of the group factor (EHS versus control subjects) on heart rate (F(1,80) = 20.6; p < 0.01), heart rate spectrum ratio (F(1,80) = 9.5; p = 0.02), and electrodermal activity (F(1,76) = 4.2; p = 0.04), whereas EEG characteristics did not differ between groups.  The Condition factor (mathematical task versus relaxed) showed main effects for heart rate (F(1,80) = 14.8; p < 0.01), heart rate spectrum ratio (F(1,80) = 7.8; p = 0.06), electrodermal activity (F(1,76) = 56.8; p < 0.01), and alpha and theta spectral bands of EEG.  Magnetic field exposure did not affect autonomous system or electroencephalographic variables of either group.  These data do not indicate that EHS patients or control are affected by low-level 60 Hz magnetic field exposure.  However, persons reporting EHS differed from the control subjects in baseline values of investigated physiological characteristics.  Perhaps EHS patients have a rather distinctive physiological predisposition to sensitivity to physical and psychosocial environmental stressors.

   In a double-blind, randomized, within participants provocation study, Rubin et al (2006) examined if people who report being sensitive to mobile phone signals have more symptoms when exposed to a pulsing mobile signal than when exposed to a sham signal or a non-pulsing signal.  A total of 60 "sensitive" people who reported often getting headache-like symptoms within 20 minutes of using a global system for mobile communication (GSM) mobile phone and 60 "control" subjects who did not report any such symptoms were included in this study.  Subjects were exposed to 3 conditions: (i) a 900 MHz GSM mobile phone signal, (ii) a non-pulsing carrier wave signal, and (iii) a sham condition with no signal present.  Each exposure lasted for 50 mins.  The principal outcome measure was headache severity assessed with a 0 to 100 visual analog scale (VAS).  Other outcomes included 6 other subjective symptoms and subjects' ability to judge whether a signal was present.  Headache severity increased during exposure and decreased immediately afterwards.  However, no strong evidence was found of any difference between the conditions in terms of symptom severity.  Nor did evidence of any differential effect of condition between the 2 groups exist.  The proportion of sensitive subjects who believed a signal was present during GSM exposure (60 %) was similar to the proportion who believed one was present during sham exposure (63 %).  The authors concluded that no evidence was found to indicate that people with self-reported sensitivity to mobile phone signals are able to detect such signals or that they react to them with increased symptom severity.  As sham exposure was sufficient to trigger severe symptoms in some participants, psychological factors may have an important role in causing this condition.

   Wallace et al (2010) conducted a randomized, double-blind, provocation study to establish whether short-term exposure to a radio system used by United Kingdom police (TETRA) base station signal has an impact on the health and well-being of individuals with self-reported "electrosensitivity" and of participants who served as controls.  A total of 51 individuals with self-reported electrosensitivity and 132 age- and sex-matched controls participated in an open provocation test; 48 sensitive and 132 control participants went on to complete double-blind tests in a fully screened semi-anechoic chamber.  Heart rate, skin conductance, and blood pressure readings provided objective indices of short-term physiological response; VAS and symptom scales provided subjective indices of well-being.  These investigators found no differences on any measure between TETRA and sham (no signal) under double-blind conditions for either controls or electrosensitive participants, and neither group could detect the presence of a TETRA signal at rates greater than chance (50 %).  When conditions were not double-blind, however, the self-reported electrosensitive individuals did report feeling worse and experienced more severe symptoms during TETRA compared with sham.

   Nieto-Hernandez et al (2011) noted that concerns have been raised about possible health effects from radiofrequency fields pulsing at around 16 Hz.  The TETRA employs signals that pulse at 17.6 Hz.  These investigators examined if exposure to a continuous wave signal at 385.25 MHz or a TETRA-like signal resulted in symptoms among users reporting sensitivity to TETRA compared to users not reporting sensitivity to TETRA.  A total of 60 sensitive and 60 non-sensitive users were exposed to 3 50-min conditions: (i) a signal with a 16 Hz component, (ii) a continuous wave condition and (iii) a sham condition.  The mean radiated power for the 16 Hz and continuous wave conditions was 250 mW.  The order of conditions was randomized and testing was conducted double-blind.  Participants reported the severity of 8 symptoms during and after each exposure, their mood state at the end of each exposure, and whether they could tell which sessions involved active signals.  Exposure to the continuous wave signal increased ratings of headache in all participants, fatigue in non-sensitive participants and difficulty concentrating in sensitive participants.  Paradoxically, it reduced sensations of itching in sensitive participants.  These effects were not observed in the condition with 16 Hz pulsing, except for those relating to concentration.  Adjusting for multiple comparisons removed most significant effects, but not those relating to itch.  The authors conclude that these findings suggested that exposure to TETRA signals is not responsible for symptoms reported by some users, although exposure to a continuous wave signal may affect symptoms.

5. Oral Nystatin for the Treatment of "Candidiasis Hypersensitivity Syndrome":

   Dismukes et al (1990) stated that candida albicans infection has been proposed to cause a chronic hypersensitivity syndrome characterized by fatigue, pre-menstrual tension, gastro-intestinal symptoms, and depression.  Long-term antifungal therapy has been advocated as treatment for the syndrome, which is most often diagnosed in women with persistent or recurrent candida vaginitis.  These investigators determined the effectiveness of nystatin therapy for presumed candidiasis hypersensitivity syndrome.  They conducted a 32-week randomized, double-blind, cross-over study using 4 different combinations of nystatin or placebo given orally or vaginally in 42 pre-menopausal women who met present criteria for the syndrome and had a history of candida vaginitis.  The outcomes studied were the changes from base line in scores for vaginal, systemic, and overall symptoms and in the results of standardized psychological tests.  The 3 active-treatment regimens (oral and vaginal nystatin, oral nystatin and vaginal placebo, and oral placebo and vaginal nystatin) and the all-placebo regimen significantly reduced both vaginal and systemic symptoms (p < 0.001), but nystatin did not reduce the systemic symptoms significantly more than placebo.  On average, the scores for systemic symptoms improved 25 % with the 3 active-treatment regimens and 23 % with the all-placebo regimen, a difference of only 2 % (95 % CI: -3 to 7 %).  As expected, the 3 active-treatment regimens were more effective than placebo in relieving vaginal symptoms (p < 0.001).  All 4 regimens reduced psychological symptoms and global indexes of distress; there were no significant differences among the treatment regimens.  The authors concluded that in women with presumed candidiasis hypersensitivity syndrome, nystatin does not reduce systemic or psychological symptoms significantly more than placebo.  Consequently, the empirical recommendation of long-term nystatin therapy for such women appears to be unwarranted.