Forty years of diarrhoea in a patient with urticaria pigmentosa

A patient with urticaria pigmentosa who gave a 40-year history of diarrhoea was found to have systemic mastocytosis with gut involvement. The radiological appearance of the gut in this disease, although not widely recognized, are specific and should be looked for carefully in patients with urticaria pigmentosa who complain of gastro-intestinal symptoms. Gastro-intestinal symptoms, due mainly to alterations in bowel motility or peptic ulceration, are said to occur in some 25-50% of cases of systemic mastocytosis (3, 6). These symptoms have usually been ascribed to generalized histamine release acting on the gut, although cases where mast cell infiltration of the bowel has occurred have also been reported (4, 5). In a review of the radiological features (2), increased gastric rugosity with or without evidence of peptic ulceration and nodular space-filling defects of the bowel mucosa were the most commonly found. Occasionally, diffuse thickening of the bowel wall was seen. It was concluded that these appearance were probably due to local release of vasoactive substances causing submucosal oedema following mast cell accumulation in the gut. Another result of such infiltration may be malabsorption (1).