Ocronosi esogena da idrochinone

A case of exogenous ochronosis associated with topical application of a hydroquinone-containing preparation is reported. The patient was a 42-year-old Nigerian woman who had intermittently applied a bleanching cream to her skin for 5 year. Examination revealed numerous discrete, pin-point, blue-black macules distributed in a symmetric fashion on the zygomatic regions and, to a lesser extent, the nose, chin, and upper and lower extremities. The sclerae, conjunctivae, ears, and oral mucosa were normal. Histopathologic examination of a skin biopsy from a dyscromic area revealed within the papillary dermis and mid reticular dermis, multiple scattered, banana-shaped or arciform, yellow-brown, swollen collagen bundles. Scrutiny of the epidermis overlying the ochronotic deposits showed evidence of a vacuolar interface dermatitis with some necrotic keratinocytes. To the best of our knowledge, these findings have not been described in patients with the endogenous form of ochronosis and could be related to the toxic effects of hydroquinone on the epidermal keratinocytes and melanocytes.