Diffuse bullous mastocytosis: clinical case study

Abstract

Introduction: Dermatological diseases are a frequent reason for pediatric consultation, with infectious diseases predominating. However, rare proliferative pathologies, such as diffuse cutaneous mastocytosis with bullous variants, present a diagnostic challenge due to their low prevalence and clinical similarity to other bullous dermatoses. This entity is characterized by massive infiltration of mast cells in the skin and the release of proinflammatory mediators, leading to variable cutaneous manifestations and potential systemic complications. The objective is to describe a case of bullous mastocytosis in an infant and highlight the relevant clinical and diagnostic aspects. Methods: We describe the case of a two-month-old female infant with generalized bullous lesions. The clinical evaluation included a detailed dermatological examination and a skin biopsy for diagnostic confirmation. Clinical follow-up was performed after the initiation of treatment. Results: The patient presented with tense blisters ranging from 2 mm to 2 cm in diameter, distributed on the scalp, trunk, and extremities, sparing the palms and soles, with residual reddish-brown macules and a positive Darier sign. As a history, at five days of age, she presented with a plantar blister initially diagnosed as miliaria. The skin biopsy revealed thin skin with spongiosis, basal hyperpigmentation, and subdermal blisters, associated with marked dermal proliferation of mature mast cells, consistent with diffuse bullous cutaneous mastocytosis. Treatment was initiated with H1 antihistamines and corticosteroids, with partial clinical improvement, followed by long-term maintenance with antihistamines. Discussion: Pediatric cutaneous mastocytosis is benign and usually manifests before the age of two. The diffuse variant is rare and can be confused with conditions such as scalded skin syndrome, epidermolysis bullosa, or bullous impetigo. The diagnosis is based on clinical and histopathological correlation. First-line treatment includes antihistamines and mast cell stabilizers, reserving systemic therapies for severe or refractory cases. Early recognition is essential to avoid complications associated with the massive release of mast cell mediators.