Identical intestinal permeability changes in children with different clinical manifestations of cow's milk allergy.

To determine the relationship between clinical symptoms of cow's milk allergy (CMA) and intestinal permeability, 51 children (mean age, 13 months) were studied during a diagnostic milk provocation test. Intestinal permeability was assessed by orally administered lactulose (4 gm) and mannitol (0.8 gm) immediately before (day 0) the milk challenge and 3 days later (day 3). Twenty-four patients evinced cutaneous symptoms and 27, gastrointestinal symptoms. The mean (95% confidence interval) urinary lactulose/mannitol recovery ratios before the milk challenge were, in both groups of patients, comparable to the level of that of control patients, 0.02 (0.01 and 0.03). A rise in lactulose/mannitol excretion ratios followed cow's milk administration by day 3 in patients with skin symptoms, 0.06 (0.03 and 0.13), as well as in patients with gastrointestinal symptoms, 0.08 (0.04, 0.17). These levels were significantly different from the control level, p = 0.003, and the prechallenge level, p = 0.01. This difference was caused by a concomitant increase in urinary recovery of lactulose and a decrease of mannitol. These results indicate that the intestinal barrier is equally altered in patients with different clinical manifestations of CMA and further suggest that enhancement of mucous membrane permeability is not a primary defect in the pathogenesis of CMA but rather a secondary phenomen, possibly caused by a hypersensitivity reaction in the intestinal mucosa.