Methylisothiazolinone in rinse-off products causes allergic contact dermatitis: a repeated open-application study.

摘要: Summary Background In recent years, the prevalence of contact allergy to preservative methylisothiazolinone (MI) has increased dramatically. Cosmetic products are one major sources exposure. Objectives To examine whether allowed concentrations MI in cosmetic rinse-off have potential cause allergic dermatitis. Methods Nineteen MI-allergic subjects and 19 controls without applied two liquid hand soaps five times per day on areas 5 × 10 cm2 ventral side their forearms. One soap contained 100 ppm MI, maximum concentration cosmetics, was used by 10 all controls. Another with 50 ppm nine subjects. As negative control, a similar that did not contain MI. The repeated open applications proceeded until positive reaction occurred or up 21 days. study conducted randomized blinded fashion. Results Ten out developed reactions seven reacted soap, while none had during 21 days application. No reactivity seen difference between statistically significant (Fisher's exact test, P ˂ 0·0001). Conclusions Rinse-off preserved more safe for consumers. level yet been identified.