Pemphigus Foliaceus in a Patient With Pre-existing Atopic Dermatitis: A Case Report.

Pemphigus foliaceus (PF) is a rare autoimmune blistering skin disease characterized by superficial erosions and crusts due to autoantibodies targeting desmoglein 1. Diagnosis can be challenging, particularly when initial presentation mimics common dermatoses such as atopic dermatitis. We report the case of a 55-year-old Syrian female initially diagnosed with severe atopic dermatitis, who presented with widespread pruritic skin lesions unresponsive to corticosteroids. Clinical deterioration with new vesiculobullous lesions prompted re-evaluation. Histopathology and serologic testing confirmed PF. The patient achieved disease control with systemic corticosteroids and immunosuppressive therapy and remains in remission after two years of follow-up. This case underscores the diagnostic complexity of PF, especially in patients with overlapping or misleading dermatologic histories. A high index of suspicion, timely biopsy, and serological confirmation are essential for diagnosis. Long-term immunosuppressive therapy combined with corticosteroids proved effective in achieving sustained remission.