What is the “frosting” effect that occurs after a chemical peel, and what does it clinically mean?

Frosting is the sudden appearance of a white, snowy appearance on certain areas of the skin, particularly during exfoliation procedures using strong acids like TCA (Trichloroacetic Acid) or high concentrations of salicylic acid. This occurs because the acid “denatures” (cooks/clots) the keratin proteins in the epidermis and dermis. The formation of frosting is a clinical indicator that the acid has reached the living layers of the skin and that a deep exfoliation process will begin in that area. The physician should neutralize the acid and stop the procedure as soon as frosting is observed; otherwise, the acid will penetrate deeper, leading to permanent chemical burns and scarring.