Miliaria Crystallina in a Case of Pachyonychia Congenita: An Unusual and Underreported Association

Abstract

Pachyonychia congenita (PC) is a rare genodermatosis characterized by hypertrophic nail dystrophy, palmoplantar keratoderma, and oral leukokeratosis. We report the case of a 5-year-old boy with classical features of PC along with the rare co-occurrence of extensive miliaria crystallina, a combination reported only once previously. The patient presented with thickened nails from infancy, widespread follicular hyperkeratosis, recurrent summer-onset vesicular lesions, and oral leukokeratosis. Histopathology confirmed features of both PC and miliaria. Based on clinical, dermoscopic, and histopathological findings, a diagnosis of PC was established. The patient responded well to a combination of oral isotretinoin, urea-based keratolytics, and topical steroid-antibiotic therapy. This case highlights a rare and unusual presentation of PC and underscores the importance of recognizing such associations for accurate diagnosis and management.