Effects of topical cyclosporin A on guinea-pig toxic contact dermatitis.

It is known that the topical application of cyclosporin A (CsA) has a significant suppressive effect on allergic contact dermatitis. In this study, we investigated the effect of topical CsA on toxic (non-allergic) contact dermatitis. Topical CsA significantly suppressed the toxic contact reaction to croton oil. This suppressive effect was short-lived and reversible. Significant inhibition of the reaction to croton oil persisted for 3 days after stopping the CsA. The toxic reaction was blocked when CsA was applied within 6 h of the croton oil application, but when application of CsA was delayed until 12 h after the oil application there was no significant suppressive effect. Topical administration of CsA could become a valuable tool for treating toxic and allergic contact dermatitis without producing the adverse reactions caused by systemic therapy.