Dermatology Online Journal

Development of lentigines in areas of resolving psoriatic plaques is a rare phenomenon that has been reported following various treatment modalities including phototherapy, topical therapies, and biologics. Although the exact mechanism is unknown, evidence suggests that the cause may be multifactorial, with factors such as skin type, sun exposure, inflammation, and immunologic cytokines all playing a potential role. Herein, we present the first reported case of a patient developing multiple lentigines following treatment of psoriasis with the IL-23 inhibitor guselkumab.