Psoriatic eruption following immunotherapy with pembrolizumab: a case report

Programmed death-1 inhibitor-induced psoriasis is an uncommon and challenging adverse event, especially when severe and in patients without a dermatological history. We report the case of a 67-year-old man, phototype 2, agronomist, diabetic, receiving pembrolizumab for the treatment of renal cancer, who, after the fifth dose, developed progressive pruritic skin lesions characterized by disseminated erythematous-scaling plaques and papules, with a psoriasis area and severity index of 36. Biopsies revealed chronic psoriasiform dermatitis with eosinophilia, compatible with an immune-mediated reaction. He had previously used moisturizers, oral bilastine, and topical corticosteroids, without improvement. Secukinumab was then introduced in an induction regimen followed by monthly maintenance, with marked improvement after the 2nd monthly dose and sustained response for 6 months. This case highlights the importance of early recognition of cutaneous manifestations associated with immunotherapy and demonstrates that selective interleukin-17A blockade can control induced psoriasis without compromising the continuity of oncologic treatment.