Antimalarials. Chloroquine, hydroxychloroquine, and quinacrine can cause blue-black skin hyperpigmentation in as many as 25% of patients. Common locations include the shins, face, oral mucosa, and subungual skin. This hyperpigmentation rarely fully resolves.2
Amiodarone. Hyperpigmentation secondary to amiodarone use typically is slate-gray in color and involves photoexposed skin. Patients should be counseled that pigmentation may—but does not always—fade with time after discontinuation of the drug.2
Heavy metals. Argyria results from exposure to silver, either ingested orally or applied externally. A common cause of argyria is ingestion of excessive amounts of silver-containing supplements.3 Affected patients present with diffuse slate-gray discoloration of the skin.
Other metals implicated in skin hyperpigmentation include arsenic, gold, mercury, and iron. Review of all supplements and herbal remedies in patients presenting with skin hyperpigmentation is crucial.
Bleomycin is a chemotherapeutic agent with a rare but unique adverse effect of inducing flagellate hyperpigmentation that favors the chest, abdomen, or back. This may be induced by trauma or scratching and is often transient. Hyperpigmentation can occur secondary to either intravenous or intralesional injection of the medication.2
Continue to: In addition to medication...