Food Protein-Induced Allergic Proctocolitis: Real-World Experience from an Italian Cohort.

Background/Objectives: Food protein-induced allergic proctocolitis (FPIAP) is a non-IgE-mediated food allergy, usually presenting as bloody stools in breastfed, well-appearing, and regularly growing infants. The aim of our study was to describe the clinical features of Italian infants affected by FPIAP and their management and natural history in a real-life setting. Methods: A retrospective, observational study was performed at two tertiary pediatric hospitals (Florence and Trieste), including FPIAP-diagnosed infants between 2012 and 2022. Results: Most of the 100 enrolled patients were breastfed (68.0%), and the majority of those who underwent diagnostic tests (n = 51) showed normal hemoglobin and total IgE levels. A maternal elimination diet was performed in 69.0%, mostly for milk only, but 40.6% underwent multiple elimination diets. The remission rate was high both in breastfed infants (76.8%) and in those who received extensively hydrolyzed formula (81.8%). Nine subjects were left on a free diet, but six were lost at follow-up. The median time of complete remission was 30 days (IQR 14-60). Culprit food reintroduction was tolerated at a median age of 8 months (IQR 6-11), in ladder modality (for hen's egg and cow's milk) in 61.7%. Nine patients relapsed (14.3%) upon reintroduction with no associated variables identified at the regression analysis. The relapse rate was slightly higher when trigger food reintroduction was attempted > 12 months (16.7%) versus <12 months (13.0%). Conclusions: In our population, FPIAP had, as expected, a benign evolution. The early reintroduction of the suspect food in a gradual manner for cow's milk and hen's egg leads to good tolerance within the first year in most patients, avoiding unnecessary elimination diets.