About 10–25% of patients with systemic lupus erythematosus (SLE) managed with antimalarials will develop cutaneous hyperpigmentation, and although the majority of such cases is attributed to chloroquine, hydroxychloroquine (HCQ) is also implicated and is likely underrecognized1.
A 52-year-old Hispanic woman with SLE and endstage renal disease receiving peritoneal dialysis presented with a 3-month history of asymptomatic, progressive darkening of her bilateral upper extremities. There was no antecedent trauma or preceding skin eruption. She had been taking HCQ 200 mg daily for 12 years. Physical examination revealed diffuse mottled and reticular hyperpigmentation with adjacent areas of ecchymosis on the bilateral upper extremities (Figure 1A). A biopsy revealed dermal deposits of iron and melanin (Figure 1B–D). A diagnosis of drug-induced dyschromia was made with a staining pattern compatible with that of antimalarial exposure.
A. Mottled and reticular hyperpigmented patches on the arms with focal ecchymosis. B. High-magnification H&E-stained section (original magnification ×400) showing scattered pigmented granules within the mid dermis, some seen within histiocytes. C–D. Perls’ Prussian blue (original magnification ×100) and Fontana Masson (original magnification ×400) stains reveal significant iron and melanin deposits within the dermis, respectively.
Presentation on the lower legs, especially shins, is classic, but other sites may be involved including mucosa and nail beds2. The pigmentation may begin within a year of treatment, but the timing of onset is variable, and contrary to HCQ-associated retinopathy, a direct association between cumulative dose or duration of therapy with the pigmentation has not been substantiated1. The pathophysiology is not well understood, but it is thought that the pigmentation is precipitated by bruising leading to hemosiderin deposition and subsequent activation of melanocytes leading to the accumulation of melanin. This hypothesis, however, is inadequate because it does not account for pigmentation on nontraumatic sites such as mucosa. Upon cessation of HCQ, some patients demonstrate partial improvement, and laser treatments may improve residual dyschromia3.
Footnotes
Written consent for publication of the photos herein has been waived because they are nonidentifiable. Institutional review board approval has been waived because this is a case report involving a single patient case that does not meet the US Department of Health and Human Services definition of “research.”
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