LAUSR

IMPORTANCE Medications as well as other substances have been linked to the development of lichenoid dermatitis. Lichen planus pigmentosus is a rare variant of lichen planus. Little is known about the possible association of lichen planus pigmentosus with drugs or other substances. OBSERVATIONS We hereby report the case of 2 women, who had a clinical and histological picture of lichen planus pigmentosus, after beginning a treatment respectively with methadone and the homeopathic remedy Calcarea Carbonica. CONCLUSIONS AND RELEVANCE We believe the substances were the most likely causative agent in both cases since the lesions began after starting methadone and the homeopathic remedy Calcarea Carbonica treatment and resolved shortly after treatment termination. The lesions improved with time and no new lesions developed during follow-up. The clinical and the pathological findings were consistent with the diagnosis of lichen planus pigmentosus. To our knowledge, this is the first report on the development of lichen planus pigmentosus after assumption of methadone or homeopathic remedies. It is very important to distinguish between idiopathic and substances-related lichen planus pigmentosus, and a careful anamnesis is fundamental to discover a potential inciting agent. This article is protected by copyright. All rights reserved.