Cellobiose/mannitol sugar absorption test in patients with dermatitis herpetiformis: a preliminary report.

An abnormal cellobiose/mannitol ratio is present in new patients presenting with dermatitis herpetiformis and in patients who have never adhered to a strict gluten-free diet. In patients with dermatitis herpetiformis in remission on a strict gluten-free diet, small bowel absorption as measured by the cellobiose/mannitol ratio is normal. It is suggested that cellobiose/mannitol ratio absorption is a useful screening test for the intestinal abnormality associated with dermatitis herpetiformis and failure of the test to return to normal could suggest poor dietary compliance.