Dapsone for Treatment of a Neutrophilic Predominant Variant of Polymorphous Light Eruption: A Case Report.

Introduction: Polymorphous light eruption (PMLE) is a self-limiting immunologically mediated photodermatitis that results in the eruption of pruritic lesions hours to days after sun exposure. Case Presentation: The case presented here highlights the clinical presentation of a 39-year-old Caucasian male with an itchy, blistering rash affecting the chest, abdomen, arms, and legs. History and examination findings were suggestive of a neutrophil predominant variant of PMLE. The rash was evaluated through laboratory testing, potassium hydroxide (KOH) microscopy, wound culture, and punch biopsy. The hematoxylin and eosin (H&E) stain results from the biopsy demonstrated eosinophilic and neutrophilic spongiosis. Various therapeutic modalities were explored in the treatment of this patient including topical steroids, oral steroids, oral antifungals, and oral antihistamines with a lack of remission of the symptoms. Due to the persistent nature of the rash and neutrophil predominance visualized on H&E, dapsone was begun with eventual cessation of symptoms and resolution of the rash. Conclusion: This case highlights the importance of scrutinizing the underlying pathophysiology of a patient's symptoms despite variations in the suspected clinical picture for effective management of symptoms.