Patch testing: pitfalls and performance

PURPOSE OF REVIEWContact dermatitis is a common disease process that includes allergic and irritant contact dermatitis. The gold standard for diagnosing allergic contact dermatitis, a type IV delayed hypersensitivity reaction, is patch testing. Patch testing is not a difficult procedure, however, there are several critical components that determine the success of the testhaving an appropriate level of suspicion for the diagnosis of allergic contact dermatitis, an adequate threshold for patch testing, the necessary experience to properly interpret the results and to determine their relevance, and the ability to thoroughly educate the patient about the condition. RECENT FINDINGSResearch shows that patch testing practices differ among individuals and specialties. The level of patch testing education, interest in, and experience with, the procedure can affect the results of the test. Some of these practice differences and how they affect the outcome of patch testing are highlighted. SUMMARYPhysiciansʼ knowledge and experience with patch testing, their level of interest and access to allergens will determine the performance of this test, the reliability of the results and the benefits gained from this procedure.