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allergen skin testing

Indications: 1) eosinophilic esophagitis [5] 2) moderate to severe atopic dermatitis [5] 3) assessment of respiratory allergies to pollens & molds 4) patients with generalized urticaria, particularly in response to a hymenoptera sting; a large localized reaction does NOT warrant allergen skin testing 5) point-of-care beta-lactam allergy skin testing (BLAST) Procedure: 1) a battery of allergens is applied in a systematic fashion via prick, scratch or intradermal injection usually on the back 2) a wheal or a flare indicates an allergic reaction to the injected substance 3) reactions are read 15 minutes after injection 4) increasing sensitivity is obtained in the order prick < scratch < intradermal injection 5) increasing specificity is obtained in the opposite order prick > scratch > intradermal injection Skin testing should be delayed at least one month after generalized urticaria. Adverse effects: - intradermal testing may be associated with potentially life-threatening systemic reactions. Clinical significance: 1) positive skin test: - identifies allergen-specific IgE - does NOT indicate a mucosal immune response to the same antigen under natural conditions 2) positive allergen skin testing: - 43% of individuals respond positively to at least 1 indoor allergen [4] - dust mites 28% - cockroach 26% - cat 17%

Related

radioallergosorbent [RAST] testing

Specific

point-of-care beta-lactam allergy skin testing (pocBLAST) skin end point titration (Rinkel method)

General

skin testing

References

  1. Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 84
  2. Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 11, 28-29
  3. Medical Knowledge Self Assessment Program (MKSAP) 11, American College of Physicians, Philadelphia 1998
  4. Arbes SJ Jr, Gergen PJ, Elliott L, Zeldin DC. Prevalences of positive skin test responses to 10 common allergens in the US population: results from the third National Health and Nutrition Examination Survey. J Allergy Clin Immunol. 2005 Aug;116(2):377-83. PMID: 16083793
  5. Bird JA, Crain M, Varshney P. Food allergen panel testing often results in misdiagnosis of food allergy. J Pediatr. 2015 Jan;166(1):97-100. PMID: 25217201