Patch testing with patients' own cosmetics and toiletries--results of the IVDK*, 1998-2002.

Patch test results with products brought in by the patients collected by the members of the Information Network of Departments of Dermatology (IVDK) between 1998 and 2002 were analysed. 5911 patients were patch tested with their own cosmetics and toiletries during this period. The 34 082 single test preparations applied to these 5911 patients were manually assigned to 1 of 26 categories, based on the EU Classification Annex I to 76/768/EEC, which had been further refined. The leave-on product category most commonly tested was 'creams, emulsions, lotions, gels and oils for the skin' (n = 3621 tested, n = 312 positive). The rinse-off product type most commonly tested was 'bath and shower preparations' (n = 1333 tested, n = 71 positive). In one-third of patients tested positive to these products, no other positive test result was observed. In the remainder, positive reactions to the fragrance mix, Myroxylon pereirae resin, methyldibromo glutaronitrile, (chloro-)methylisothiazolinone, 2-bromo-2-nitropropane-1,3-diole and further ingredients of cosmetics and toiletries were more common than in product-negative patients. However, in view of the potential for false-positive reactions mainly to rinse-off products, the results must be interpreted with caution. In conclusion, testing of patients' own products can be regarded as efficient and safe, if in accordance with current recommendations.