Clinical characteristics and outcomes of paradoxical palmoplantar pustulosis during secukinumab therapy in biologic-naïve patients with plaque psoriasis: a retrospective case series

BACKGROUND: Palmoplantar pustulosis (PPP) is an uncommon paradoxical reaction associated with biologic therapy. However, secukinumab-induced PPP remains poorly characterized, particularly in biologic-naïve patients with plaque psoriasis. OBJECTIVE: To describe the clinical features, laboratory findings, management, and outcomes of biologic-naïve patients who developed PPP during secukinumab therapy. METHODS: We conducted a retrospective case series of biologic-naïve adults with moderate-to-severe plaque psoriasis who developed new-onset PPP during secukinumab treatment. Clinical characteristics, laboratory findings, treatment modifications, and outcomes were reviewed. RESULTS: Seven biologic-naïve patients were identified. PPP developed after a median of 10 weeks following secukinumab initiation. All patients developed de novo palmoplantar pustular lesions without a prior history of PPP. Peripheral neutrophilia was observed in all patients and was accompanied by significant increases in neutrophil and white blood cell counts compared with baseline, without evidence of infection. Secukinumab was discontinued in all cases. Clinical improvement occurred in six patients, and complete resolution was achieved in two patients after switching to tildrakizumab. CONCLUSIONS: PPP may occur as a paradoxical adverse event during secukinumab therapy, even in biologic-naïve patients. Early recognition and appropriate treatment modification are important for optimal management.