The aim of this study was to identify the clinical features and natural history of dietary protein induced proctocolitis (DPIPC) and to detect the causative foods of DPIPC, and to evaluate the effect of elimination of the foods on the course of the disease.

Between March 2003 and July 2004, data from 30 consecutive patients with DPIPC who were followed for over 6 months, was reviewed. The diagnostic criterion used for DPIPC was an increase in the number of eosinophils in the lamina propria (≥60 per 10 high-power fields). In breast feeding mothers, 5 highly allergenic foods were eliminated from the maternal diet for 7 days, namely, allergenic food groups such as dairy products, eggs, nuts and soybean, fish and shellfish, and wheat and buckwheat. We observed the disappearance or appearance of hematochezia after elimination or challenge with the offending foods.

Before diagnosis infants were breast-fed (93.3%) or formula-fed (6.7%). Mean age at symptom onset was 11.5±5.1 (5~24) weeks, and mean age at diagnosis was 17.8±9.5 (8~56) weeks. Duration from symptom onset to diagnosis was 6.3±6.7 (0~36) weeks. Mean peripheral blood eosinophil count was 478±320 (40~1,790)/mm³ and eosinophilia (>250/mm³) was observedin 90.0% of patients. None of patients were found to have an increased serum IgE level. Of 15 patients that received sigmoidoscopy, nodular hyperplasia with erosion was observed in 93.3%. Of 27 patients whose mother ate the diet eliminated the 5 food groups, hematochezia diappeared in 74.1% of patients. Offending foods were identified as dairy products (37.5%), wheat and buckwheat (27.5%), fish and shellfish (20.0%), nuts and soybean (7.5%) and eggs (7.5%). A free maternal diet without patient's clinical symptoms was achieved at 29.4±8.7 (9~44) weeks of patient's age, and a free baby diet without blood in stools was achieved at 37.5±9.7 (12~56) weeks of age.

DPIPC commonly occurs in exclusively breast-fed babies. Elimination of the above-mentioned 5 hyper-allergenic food groups from the maternal diet for 7days enables the detection of the offending foods. DPIPC is a transient disorder and 96.0% of patients can tolerate the offending foods at 12 months of age.