Bullous urticaria pigmentosa is a rare disease which is caused by excessive numbers of mast cells that produce lesions in the skin and/or organs. the authors report one case of a 15-month-old boy who has got bullosa in scalp, face and neck since he was 4 months old. The disease recurred 6 times with similar features: the face and conjunctiva, sclera got red, lasted for 10-15 minutes, intense itching led the patient to scratch
and the rubbing skin appeared blisters, bullosa 1-7 mm in dimension
the lesions linked to developing bigger bullosa filled with yellow fluid in the erythema background. This condition was together with diarrhea 3-4 times per day, lasted until 2-3 days after the day when there was no new bullosa. He also had fainting, rolled eyes for 2-3 minutes, then enuresis and returned to normal. Darier's sign was positive. Skin biopsy: dense'of mastocyte. Through the history, examination and investigation, he was diagnosed with bullous urticaria pigmentosa. After 1 week of treatment, the lesion reduced and he was discharged.