A Case Report of Sporadic Pemphigus Foliaceus in a 3-year-old Filipina: A Rare Pediatric Presentation

Chronic blistering dermatoses in pediatric patients present a diagnostic challenge owing to their rarity and resemblance to infectious disorders. Misdiagnosis often leads to prolonged morbidity and inappropriate treatments. This case highlights a child with a progressive vesiculobullous dermatosis unresponsive to initial therapies that revealed an unexpected etiology. A previously healthy 3-year-old Filipina presented with an 8-month history of vesiculobullous eruption. It began as a solitary vesicle on the forehead and gradually spread to the face, trunk, and extremities. Lesions were intensely pruritic, occasionally painful, and accompanied by intermittent fever. Initially diagnosed with bullous impetigo, she received multiple antibiotics without improvement. Herbal remedies further aggravated her condition. On admission, she had generalized erythema with yellowish scales, crusts, erosions, and flaccid vesicles and bullae without mucosal involvement. Nikolsky’s and Asboe–Hansen signs were positive. Differential diagnoses included staphylococcal scalded skin syndrome, autoimmune blistering diseases, and severe drug reactions. Histopathology revealed a subcorneal split with acantholytic keratinocytes. Direct immunofluorescence demonstrated intercellular deposition of immunoglobulin G (IgG) and C3 within the epidermis. ELISA confirmed markedly elevated anti-desmoglein 1 IgG (>200 RU/mL), consistent with pemphigus foliaceus (PF), an autoimmune blistering disorder exceptionally rare in children. Her Pemphigus Disease Activity Index (PDAI) score was 64, signifying severe disease. She was started on oral prednisolone (1.5 mg/kg/day) and intravenous antibiotics for concurrent pneumonia. After 2 weeks, there was marked improvement, with resolution of erosions and bullae, postinflammatory hyperpigmentation, and PDAI reduction to 28. With fewer than 40 nonendemic cases reported worldwide, including one of the first in the Philippines, pediatric PF is extremely uncommon. Its resemblance to common pediatric skin infections underscores the need to consider autoimmune blistering disorders in persistent dermatoses. Immunopathologic assessment is essential for accurate diagnosis, and systemic corticosteroid therapy can result in rapid recovery. Long-term outcomes remain uncertain given the extremely small number of reported cases.