Druginduced Pityriasis rubra pilaris

Abstract

Pityriasis rubra pilaris (PRP) is a rare inflammatory dermatosis. We report an atypical case of PRP in a 29-year-old male with Philadelphia chromosome-positive acute lymphoblastic leukemia in 3 ^rd relapse on ponatinib, who developed asymptomatic scaly plaques on the trunk and upper limbs 6 months after starting ponatinib treatment. The histopathology confirmed PRP with alternating orthokeratosis and parakeratosis, along with follicular plugging. Notably, the patient lacked palmoplantar keratoderma, a feature often absent in drug-induced PRP. The management included topical corticosteroids, antihistamines, and ponatinib cessation. This case highlights a rare adverse event associated with ponatinib, emphasizing the importance of recognizing atypical presentations and the role of histopathology in diagnosis.