Exogenous ochronosis. An update on clinical features, causative agents and treatment options.
Exogenous ochronosis is clinically and histologically similar to its endogenous counterpart; however, it exhibits no systemic effects and is not an inherited disorder. It is characterized by an asymptomatic hyperpigmentation of the face, sides and back of the neck, back, and extensor surfaces of the extremities. The associated ochronotic discoloration most commonly results from use of products containing hydroquinone. It also occurs following use of antimalarials and products containing resorcinol, phenol, mercury or picric acid. The etiology of hydroquinone-induced hyperpigmentation in exogenous ochronosis remains speculative. The majority of patients with this condition are Black, but it has been reported to occur in Hispanics and Caucasians. Exogenous ochronosis is prevalent among South African Blacks, but is believed relatively uncommon within the US. The reasons for this phenomenon are not clear, but it could be a result of the use of skin care products containing resorcinol in combination with hydroquinone or the use of hydroquinone in a hydroalcoholic lotion. Treatment of this condition is difficult. The offending agent must be avoided, but improvement occurs only slowly. A number of topical agents have been studied as have dermabrasion and the use of lasers. Controlled studies in larger numbers of patients are require to determine the true efficacy of newer treatments.
Levin
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University of California, San Francisco Medical Center, Department of Dermatology, San Francisco, California, USA.
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D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D002424:Caustics / Q000627:therapeutic use; D003358:Cosmetics / Q000009:adverse effects; D017679:Cryotherapy; D003869:Dermabrasion; D003879:Dermatologic Agents / Q000009:adverse effects; D005260:Female; D006801:Humans; D006873:Hydroquinones / Q000009:adverse effects; D015994:Incidence; D007641:Keratolytic Agents / Q000627:therapeutic use; D053685:Laser Therapy; D008875:Middle Aged; D009794:Ochronosis / Q000139:chemically induced* / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy; D012118:Resorcinols / Q000009:adverse effects; D017592:Skin Care; D013019:South Africa / Q000453:epidemiology; D013473:Sunscreening Agents / Q000627:therapeutic use; D013752:Tetracycline / Q000627:therapeutic use; D013997:Time Factors; D014212:Tretinoin / Q000627:therapeutic use; D014238:Trichloroacetic Acid / Q000627:therapeutic use
D000305:Adrenal Cortex Hormones; D000900:Anti-Bacterial Agents; D002424:Caustics; D003358:Cosmetics; D003879:Dermatologic Agents; D006873:Hydroquinones; D007641:Keratolytic Agents; D012118:Resorcinols; D013473:Sunscreening Agents; D014212:Tretinoin; D014238:Trichloroacetic Acid; D013752:Tetracycline; C031927:hydroquinone; C031389:resorcinol