Food allergy and intolerance: response to intestinal provocation monitored by endosonography

Objective: Objective assessment of adverse reactions to food is a long-felt want. We report our preliminary experience with a new endosonographic allergen provocation test. Methods: Twenty patients were examined, seven patients having food allergy and 13 having food intolerance. The duodenal mucosa was challenged with allergen extracts via a nasoduodenal tube. The responses were recorded using a miniprobe for endosonography through the tube. Thereafter, intestinal lavage was performed by giving 2 l PEG solution containing 50 μCi ⁵¹CrEDTA. The gut lavage fluid and urine for 5 h were collected. Results: Increased mucosal thickness in response to provocation was recorded in 11 patients, but not more often or pronounced in the allergic than in the intolerance group. Interestingly, increased mucosal thickness associated with a new echogenic layer was seen in two patients and a sustained duodenal contraction, lasting 15–20 min associated with pain, in another two. Intestinal permeability and inflammatory mediators were not significantly different in the two groups. Conclusion: In patients with self-reported adverse reactions to food abnormal responses to duodenal provocation may be recognised by endosonography. However, neither endosonography nor intestinal permeability or faecal calprotectin responses were able to distinguish between food allergy and intolerance. Sustained duodenal contractions in response to food might be a cause of abdominal pain.