Pembrolizumab-related hand and foot skin reaction.

Hand and foot skin reaction (HFSR), usually associated with tyrosine kinase inhibitors, is characterized by painful erythema and hyperkeratosis at palmoplantar pressure points. HFSR differs from the more widely recognized chemotherapy-induced hand-foot syndrome (HFS) in terms of both clinical and histopathological features. Here we present the case of a 79-year-old man with advanced lung adenocarcinoma who developed grade 3 HFSR after receiving pembrolizumab, a PD-1 inhibitor. The patient initially presented with erythema, desquamation, and hyperkeratotic plaques on the palms and soles, followed by the development of vesiculobullous lesions. Histopathological findings supported the clinical diagnosis. Treatment included discontinuation of pembrolizumab, along with systemic and topical corticosteroids and salicylic acid, with marked improvement and resolution after about 2 months. Given the impact on quality of life and treatment continuity, clinicians should monitor for HFSR in patients receiving immune checkpoint inhibitors (ICIs) to allow for timely intervention.