Drug-Induced Hyperpigmentation: Review and Case Series

Background: Hyperpigmentation is a common dermatologic problem that may have substantial impact on the patient, since it affects the appearance and quality of life, and may influence treatment adherence. There are few studies of drug-induced hyperpigmentation. Methods: We studied drug-induced hyperpigmentation in patients attending an outpatient dermatology clinic in the Western Area of Valladolid (Spain) from August 1, 2017 to April 20, 2018. Results: The incidence of drug-induced hyperpigmentation was 1.31% in patients attending a first dermatology consultation in the study period. Of the 16 patients, 8 were taking more than 1 drug. The most frequent drugs identified were nonsteroidal anti-inflammatory agents (25%), antihypertensive agents (18.75%), antimalarials (12.5%), antibiotics, antineoplastic agents, psychoactive agents, simvastatin, allopurinol, amiodarone and mucolytic (6.25% each). Hyperpigmentation was found in the mucosa in 25% of patients and in photograph-exposed areas in 37.5%. Discussion: Diagnosing drug-induced hyperpigmentation is a dermatologic challenge. A differential diagnosis with hyperpigmentation caused by endocrine and metabolic disorders, the most closely-related disorders to drug-induced hyperpigmentation, and with hyperpigmentation of idiopathic origin, should be conducted. Drug-induced hyperpigmentation is a relatively frequent reason for consultation, especially in polypharmacy patients. The sample may have been biased as many patients receiving treatments frequently associated with drug-induced hyperpigmentation, such as antineoplastic drugs, are diagnosed and treated by other specialties, such as oncologists. Conclusion: Family physicians and specialists should consider drugs as a cause of hyperpigmentation to facilitate the correct diagnosis and treatment.