Exogenous ochronosis following hydroquinone for melasma.

A female Indian farmer with melasma developed progressive worsening of facial pigmentation while using topical hydroquinone. It manifested as bluish-black pigmentation, confirmed microscopically as ochronotic change, i.e. exogenous ochronosis (EO). Failure to follow adequate sun protective measures and usage of overly high concentrations of hydroquinone were the most likely causes of EO in this case. It is necessary to recognize this disorder at the earliest stage to avoid treatment disappointments.