A married hindu female from a village presented with a hypopigmented lesion at the centre of forehead where she used to put bindi. Agent responsible for this lesion is:

Bindi adhesive material was found to contain 80% para-teiary- butylphenol which causes chemical leukoderma in this patient. Chemical leukoderma: Occupational exposure to chemicals that have a destructive effect on melanocytes can result in chemical leukoderma. Common agents causing chemical leukoderma: Para-teiary butylphenol Para-teiary butyl catechol Monobenzylether of hydroquinone (MBEH) Hydroquinone The depigmentation caused by chemicals is difficult to distinguish from idiopathic vitiligo. The former usually stas at the hands and forearms, presumptive sites of contact, but depigmentation at a distance is also possible. Chemical leukoderma spreads by coalescence of small macules, whereas the sudden appearance of large patches with perifollicular sparing is more suggestive of vitiligo. Chemical leukoderma is very likely if several exposed workers develop depigmentation. Ref: Lapeere H., Boone B., De Schepper S., Verhaeghe E., Van Geel M., Ongenae K., Van Geel N., Lambe J., Brochez L. (2012). Chapter 75. Hypomelanoses and Hypermelanoses. In L.A. Goldsmith, S.I. Katz, B.A. Gilchrest, A.S. Paller, D.J. Leffell, N.A. Dallas (Eds), Fitzpatrick's Dermatology in General Medicine, 8e.