Drug-induced pigmentation and/or hyperpigmentation may be caused by numerous drugs through a number of differing mechanisms. There may be a stimulation of increased melanin production or deposition of the drug or its metabolites in the epidermis and/or dermis. Perhaps the most common reaction is postinflammatory hyperpigmentation, as typically seen following inflammatory drug eruptions or fixed drug eruptions. A further mechanism of drug-induced pigmentation is the production of new pigment such as increased lipofuscin synthesis.

Increased melanin most often produces a brownish pigmentation in the dermis. When active compounds deposit in the dermis, however, there may be associated red-brown, blue-black, blue-gray, purple, or slate discoloration.

There are certain classes of drugs that are more commonly implicated in causing skin, mucous membrane, and nail pigmentation. These include antimalarials, some antimicrobials, heavy metals, antineoplastic (chemotherapeutic) agents, and psychotropics and anticonvulsants. NSAIDs and antiretrovirals have also been noted as causing specific pigment changes. Chronic use of kratom, an opioid-like supplement available over the counter, has been associated with photodistributed hyperpigmentation, often of the face and hands.

Related topics: drug-induced flagellate pigmentation, amiodarone drug-induced pigmentation, minocycline drug-induced pigmentation, drug-induced hypopigmentation, drug-induced oral pigmentation, drug-induced nail pigment, fixed drug eruption