In vivo removal of the horny layer with formic acid

An alternative to stripping for removing the horny layer has been devised. Occlusive application of 5-7% aqueous formic acid for 24 h induces a separation of the stratum corneum. The inflammatory response is minor and there is little discomfort. The method is useful for studying the effect of various chemicals and physiological agents on barrier-free skin in vivo. Additionally, the influence of creams and ointments on wound healing may be accurately assessed.