A Rash Hypothesis

A CLINICAL PROBLEM-SOLVING article by Anne Liu from Brigham and Women's Hospital, Boston.
A 40-year-old woman presented with diarrhea, reporting to her physician that she had been having loose stools for 2 years, progressing over the previous 6 months to 15 large-volume, watery stools daily, including nocturnal stools. She had also been vomiting over the previous 2 months.
The patient had had a mild rash since infancy, characterized by fixed pink patches on her trunk and limbs that became red and pruritic when scratched or exposed to sun and heat. She reported that in adulthood the patches had become smaller and more diffuse, and over the previous year the itching had become more intense. She also had long-standing facial flushing, brought on by exertion or strong emotion. Aspirin caused flushing and stomach irritation. She did not drink alcohol because even a few sips brought on nausea and abdominal pain.
On examination, the abdomen was distended, with active bowel sounds, and was soft and nontender, without a fluid wave. As measured by percussion, the liver span was 18 cm, with a firm inferior edge.
Chronic diarrhea associated with weight loss requires a search for underlying disease. In this case, the differential diagnosis was guided by recognition of the relevance of the long-standing rash and flushing.
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