Novel Histopathologic Features of Diffuse Blue-Gray Hyperpigmentation Associated With Kratom Use: A Case Report and...

Drug-induced hyperpigmentation accounts for 10%-20% of acquired pigmentary disorders and can be misdiagnosed for other causes such as melasma, post inflammatory changes, or heavy metal deposition. Kratom (Mitragyna speciosa), a Southeast Asian plant with an opioid-like profile, has been increasingly used in the United States for several conditions such as pain, mood disorders, and opioid withdrawal. While neuropsychiatric and liver toxicity adverse effects are documented, hyperpigmentation, and skin changes remain poorly recognized.

We describe a 38-year-old female with a history of Hashimoto's thyroiditis and seizure disorder who developed a progressive blue-gray hyperpigmentation over 3 years. The hyperpigmentation was initially confined to the nose and subsequently spread to the face, neck, chest, upper back, and arms. It was initially diagnosed and treated as melasma without improvement. Skin biopsies revealed basal layer hyperpigmentation and dermal melanophages. Fontana-Masson staining demonstrated an admixture of black melanin granules and distinct red-brown intracytoplasmic pigment, consistent with Kratom-associated drug deposition. These findings were consistent with drug-induced hyperpigmentation. A comprehensive medication review history excluded commonly implicated drugs. Upon further questioning, the patient disclosed prior use of kratom tea for approximately 18 months, which was discontinued around the time of the clinical presentation.

This case highlights the importance of thorough exposure history, including herbal supplements, in the workup of atypical hyperpigmentation and highlights novel histopathological features of Kratom-associated hyperpigmentation that expand the current understanding of drug-induced cutaneous changes.