Subcorneal pustular dermatosis masquerading as herpes zoster

ABSTRACT Introduction: Subcorneal pustular dermatosis is a rare neutrophilic dermatosis characterized by the development of sterile subcorneal pustules that favors flexural areas and is more common in women. Case Report: A 48-year-old male presented with recurrent attacks of pustular eruptions over the buttocks over the past one and half years. The lesions would fade in a week, leaving mild hyperpigmentation with a 2 to 3 months gap between episodes, with no systemic symptoms. On examination, there were grouped papules, vesiculopustules on an erythematous base over the left buttock. Routine blood investigations were normal. Grams stain, Tzanck smear, and Potassium hydroxide (KOH ) mount all yielded negative results. A subcorneal pustule filled with neutrophils was noted in the skin biopsy and Direct immunofluorescence (DIF) was negative. He was kept on Dapsone 100 mg once daily, and the lesions were under control in 2 weeks with no further recurrences for 1-year period of follow-up. Discussion: Recurrent pustular eruptions in adults is not an uncommon problem but the differential diagnosis of pustular skin disorders is extensive. The duration, distribution, associated features, and systemic manifestations may provide clues to the etiology of cutaneous pustular eruptions. Herein we report an uncommon presentation of Subcorneal pustular dermatosis (SCPD) which was confirmed by Histopathological examination (HPE), DIF, and its response to Dapsone.