Time Course Until Tolerance for Food Protein-Induced Allergic Proctocolitis Varies by the Causal Food.

BACKGROUND

For food protein-induced allergic proctocolitis (FPIAP), published information on the time until tolerance for each causal food and their combinations remains scarce.

OBJECTIVE

To determine time until tolerance for individual causal foods, causal foods in combination, and factors affecting tolerance development.

METHODS

Of the 91 patients diagnosed with FPIAP between March 2019 and March 2020, 84 patients with at least 3 years of follow-up were evaluated in this prospective cohort.

RESULTS

The median age of the patients was 50 months at last evaluation (interquartile range [IQR]: 47-54 months), and 52.4% were male. The tolerance development rate was 36.6% in the first year, 88.9% in the second year, 96.4% in the third year, and 97.6% after the age of 3 years. The overall median tolerance development time was 15.5 (IQR: 12-22.5) months. For each causal food, cow's milk (CM), beef, wheat, eggs, and nuts, median times until tolerance were 13 (IQR: 12-18), 13 (IQR: 12-18), 14 (IQR: 10.7-16), 16 (IQR: 12-24), and 24 (IQR: 22.5-36.5) months, respectively. In multiple food allergies (MFA), the presence of eggs significantly prolonged the time until tolerance, whereas the presence of beef did not. Multivariate regression analysis revealed that MFA presence (odds ratio [OR]: 12.11, 95% confidence interval [CI]: 1.23-118.12, P = .03), atopic dermatitis (AD) at onset (OR: 4.04, 95% CI: 1.15-14.25, P = .03), and the absence of a pet at home (OR: 0.23, 95% CI: 0.06-0.87, P = .03) were associated with delayed tolerance. The presence of IgE-mediated food allergy at onset was also associated with delayed tolerance (P = .02).

CONCLUSIONS

Tolerance development times to egg and nuts were longer than those to CM, beef, and wheat in FPIAP. Delayed tolerance appears to be due to the specific food combinations rather than multiple foods.