title: Mystery of the disappearing allergen: published allergens rarely seen again.
abstract: Patch testing is an important tool in the diagnosis of allergic contact dermatitis. Although this technique can be accurate, occasionally the results may be inconclusive. A previously positive result to an allergen may become negative upon repeat testing, and this may complicate the process of achieving a definitive diagnosis. There are some potential explanations for such inconsistencies, including the Excited Skin Syndrome, irritant reactions, a need to repeat the diagnostic algorithm, "rogue" reactions, and "contact allergy." These explanations should be taken into account when interpreting these results. However, further knowledge is needed to solve the mystery of an allergen that subsequently disappears.
authors.affiliation: University of California Medical School, San Francisco, California 94143-0989, USA. tamar.zapolanski@gmail.com
authors.forename: Tamar
authors.initials: T
authors.lastname: Zapolanski
authors.forename: Howard I
authors.initials: HI
authors.lastname: Maibach
mesh_terms: D000465:Algorithms; D000485:Allergens; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis* / Q000276:immunology; D017453:Dermatitis, Irritant / Q000175:diagnosis* / Q000209:etiology; D019317:Evidence-Based Medicine; D005189:False Positive Reactions; D006801:Humans; D007509:Irritants / Q000009:adverse effects*; D010328:Patch Tests; D010506:Periodicals as Topic; D011237:Predictive Value of Tests; D015203:Reproducibility of Results
chemical_list: D000485:Allergens; D007509:Irritants