[Diffuse cutaneous mastocytosis of an infant: A case report].

Mastocytosis is a group of diseases related to abnormal accumulation and proliferation of mast cells in one or more organs. They may be associated with an acquired point mutation and the activation of the receptor tyrosine-kinase c-KIT of CFS (mast cell growth factor). The clinical manifestations are varied and secondary to the release of mast cell mediators and/or infiltration of various organs. There are two main types of mastocytosis: pure cutaneous mastocytosis and systemic mastocytosis when more than two organs are involved in mast cell infiltration (bone marrow, gastrointestinal tract, bone, liver and spleen, lymph nodes). Mastocytosis affects children in two thirds of cases, most frequently as an isolated cutaneous form. The most common clinical form in children is urticaria pigmentosa and solitary mastocytoma; bullous diffuse mastocytosis is rare. We report the case of an 8-month-old infant who presented with a diffuse pruritic bullous eruption. The histology and immunohistochemistry results were suggestive of mastocytosis. A serum tryptase test yielded positive results. Laboratory investigations did not identify systemic involvement. The patient was given antihistamine H1 medication and local care. Advice regarding the disease was offered to the parents. The course of the disease was marked by a decrease in the number of blisters and attenuation of the pruritus at the 6-month follow-up. This observation emphasizes the importance of awareness of this rare entity, which should be considered in all cases of bullous dermatosis in children, thereby allowing for early treatment.