Patch testing with the patients' own products

Abstract

Patch testing with the baseline series may detect only 40-70% of the responsible allergens in the diagnosis of contact dermatitis. Using additional commercially available test series will detect another 25% of the relevant allergens. Only about 10% will be recognized, if the patient's own materials are patch tested. In this chapter, detailed guidelines for various products will be given: cosmetics (leave on and wash-off type), hair dressing, disinfecting agents, clothing, plants, construction materials, metal working fluids etc. The test concentration is crucial, because some of these materials are irritants and may even cause necrotic reactions, if tested undiluted. Before testing, detailed information about chemistry, pH, toxicity, and sensitization properties should be obtained. A semi-open test without occlusion is helpful for materials with irritant potential. A dilution series, control testing on informed volunteers, and repeated open application tests have frequently identified new contact allergens in various occupations and in products contacting the skin in daily life. © 2011 Springer-Verlag Berlin Heidelberg.