Contact depigmentation from free para-tertiary-butylphenol in bindi adhesive

100 consecutive cases of contact depigmentation due to bindi during a period of 11 months were studied. Bindi adhesive material was found to contain 80% para-tertiary-butylphenol (PTBP), by thin-layer chromatography, infrared spectrophotometry and high-pressure liquid chromatography. The possibility of hypersensitivity to PTBP was ruled out as none of the 15 patients tested with 2% PTBP and 1% para-tertiary-butylphenol-formaldehyde resin gave any positive reactions. Development of depigmentation could have been due either to individual susceptibility or to constant use for a prolonged period. The area of contact being very small, generalised vitiligo as a result of systemic absorption appeared to be a remote possibility.