An Occurrence of Eosinophilic Folliculitis and Alopecia Associated with a Sustained Complete Response to Mogamulizumab in Sézary Syndrome: A Case Report

This case report discusses a 72-year-old woman with Sézary syndrome (SS) who achieved a complete response (CR) after treatment with mogamulizumab, a monoclonal antibody targeting CCR4, following the failure of previous therapies. Despite the CR, she developed eosinophilic folliculitis (EF) and alopecia, which responded to topical corticosteroids but did not result in hair regrowth. The EF persisted as diffuse erythema without pustules or pruritus after mogamulizumab was withdrawn. The report suggests a potential link between EF and sustained clinical response to mogamulizumab, highlighting the need for regular monitoring to prevent SS relapse and calling for prospective studies to confirm this association.