[Bullous mastocytosis in a child].

We report a case of bullous mastocytosis in a 30-month-old girl, who developed disseminated pruritic urticarial and bullous lesions on the trunk accompanied by episodes of vomiting and generalized flushing. Her problems began at the age of 6 months. Her stool was repeatedly positive for occult blood. Histamine and 5-hydroxytryptamine were measured in the urine and serum; urine 5-hydroxytryptamine levels were elevated. In addition, trypsin and chymotrypsin levels were raised in the blister fluid. Metachromatic staining of the mast cells in a skin biopsy specimen confirmed the diagnosis. A combination of oral disodium cromoglycate and ketotifen produced a dramatic improvement of the cutaneous and gastrointestinal features.