Acute generalised exanthematous pustulosis in a patient on pembrolizumab for palliative treatment of lung adenocarcinoma

We describe a rare case of acute generalised exanthematous pustulosis (AGEP) occurring during pembrolizumab therapy in a patient with metastatic lung adenocarcinoma and longstanding chronic plaque psoriasis. Clinical and histopathological findings confirmed AGEP rather than generalised pustular psoriasis, and cessation of pembrolizumab and treatment with acitretin led to complete resolution. This case highlights the importance of early recognition and multidisciplinary management of immunotherapy-related cutaneous toxicity.