Colon in food allergy.

The colon is a site of allergic reaction to food proteins. The most common manifestation is allergic proctocolitis. Although frequent in infancy, it may also affect older children. The diagnosis of allergic proctocolitis is mainly based on clinical and histological grounds, but there is a risk of overdiagnosis; challenge is strongly recommended to avoid unnecessary and expensive formula or changes in maternal diet that may discourage continuation of breast-feeding. The benign clinical course and the spontaneous resolution in most infants suggest the need for further prospective studies to validate markers that allow the identification of those children needing a dietary approach. It remains to be assessed whether lymphoid nodular hyperplasia of the colon is a manifestation of food allergy. Finally, allergic proctitis may present clinically with refractory constipation; the true prevalence of food allergy-related constipation remains to be assessed.