Photodistributed Hyperpigmentation in a Chronic Kratom User: Histologic and Elemental Characterization

Kratom (Mitragyna speciosa) is a plant-derived supplement increasingly used in the United States for chronic pain and mood elevation due to its opioid-like effects. While systemic side effects have been described, cutaneous manifestations have rarely been reported. We report a case of striking photodistributed dyspigmentation in a chronic kratom user, with a detailed description of the histologic and elemental analysis findings. A 37-year-old Soldier taking kratom for lower back pain presented with asymptomatic blue-gray pigmentation involving his face, neck, and dorsal hands. Biopsy revealed pigment-laden macrophages within the superficial dermis, a mild perivascular and periadnexal lymphohistiocytic infiltrate, and a slightly thickened basement membrane. Special stains confirmed the pigmented particles as melanin-like. Scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDXA) demonstrated sulfur-containing material, consistent with phaeomelanin and/or a drug metabolite melanin-like complex. This case expands the clinicopathologic understanding of kratom-associated dermatoses and illustrates the utility of SEM-EDXA in identifying exogenous or drug-induced pigmentation.