Localized Segmental Facial Pemphigus Foliaceus: A Rare and Atypical Presentation

Abstract

Background: Pemphigus foliaceus (PF) is a rare autoimmune blistering disorder caused by IgG4 autoantibodies targeting desmoglein 1, leading to superficial intraepidermal acantholysis. While typically presenting with widespread lesions, localized forms are exceptionally rare. Objective: To describe a unique case of localized pemphigus foliaceus confined to the left hemiface in a 70-year-old woman, highlighting its diagnostic challenges and successful therapeutic approach. Case Presentation: A 70-year-old woman with no significant past medical history, present a one year history of eroded, erythematous, crusted lesions on the left side of her face. The lesions had been treated unsuccessfully with topical antifungals, topical corticosteroids, antibiotics, and oral antibiotics with no amelioration. Upon clinical examination, a non-pruritic, non-painful, scaly erythematous plaque was observed, localized to the left hemiface, involving the cheek and left periorbital region. There were no other lesions on the rest of her skin, mucous membranes, or hair. Histopathology and direct immunofluorescence confirmed the diagnosis of PF. The patient was treated with high-dose systemic corticosteroids (1.5 mg/kg/day prednisone) and rituximab, resulting in complete lesion resolution. No progression to generalized disease was observed. Conclusion: This case underscores the exceptional rarity of localized pemphigus foliaceus, particularly when confined to a single hemiface. Its atypical presentation can mimic other dermatological conditions, posing diagnostic challenges