Contact depigmentation caused by an azo dye in alta

Abstract

Alta, a scarlet‐red solution used by some Indian women as a cosmetic to colour their feet, was found to be associated with depigmentation at the site of application. Chromatographic and spectroscopic analysis of 3 brands of alta confirmed the presence of 2 dyes: Crocein Scarlet MOO (CSM) (brilliant crocein) and rhodamine B (tetraethyl rhodamine). Patch testing produced depigmentation at the site of application of alta, CSM and para‐phenylenediamine (PPD). Although PPD has been reported to produce leukoderma, azo dyes have not previously been reported as depigmenting agents.