Pigmented colloid milium associated with exogenous ochronosis in a farmer with long-term exposure to fertilizers

摘要

Colloid milium is a rare cutaneous deposition disorder characterized by translucent papules developing on sun-exposed regions such as the face, neck and dorsal aspects of the hands and back. Exogenous ochronosis is caused by the accumulation of homogentisic acid resulting from long-term application of certain topical agents. Histology is characterized by yellow-brown pigment deposits in the papillary dermis. Prolonged use of hydroquinone may result in the development of the pigmented form of colloid milium, sometimes in association with ochronosis.