Erythema dyschromicum perstans (EDP) is a form of acquired dermal macular hyperpigmentation characterised by well-circumscribed round to oval or irregular patches on the face, neck and trunk that are grey in colour. It is a form of acquired dermal macular hyperpigmentation. Erythema dyschromicum perstans is also called ashy dermatosis (of Ramirez), because of its colour.

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It can affect people of any age, but appears to be more frequent in young adults. Women are affected more often than men.

The cause of EDP is unknown - suggestions include the effects of : genetic susceptibility, contact allergy to cosmetics and hair dye, toxic effects of chemicals, whipworm infestation, viral infections and the adverse effect of drugs and medications.

Further info DermNetz, NZ