Analysis of Clinical Characteristics of Refractory Food Protein-Induced Allergic Proctocolitis.

Background/Objectives: Food protein-induced allergic proctocolitis (FPIAP) is a non-immunoglobulin-E-mediated allergic colitis. Most cases resolve after 1 year of age, but delayed resolution and growth retardation may occur in some refractory cases. We aimed to explore the clinical characteristics, treatment approaches, and outcomes of such pediatric patients. Methods: We retrospectively analyzed 35 patients with refractory FPIAP at our center between January 2015 and January 2025. Patients were categorized into early- and non-early-onset groups according to timing of symptom onset; various clinical data were collected and treatment regimens were monitored. Results: The proportion of patients with growth retardation was significantly higher in the non-early onset group than in the early-onset group (73.3% vs. 35.0%, p = 0.041), whereas hemoglobin levels were higher in the early-onset group (118.95 ± 11.26 g/L vs. 107.93 ± 14.61 g/L, p = 0.017).The proportion of corticosteroid use was significantly lower in the early-onset group (15.0% vs. 60.0%; p = 0.011). During follow-up, among 35 patients, 14 (40%) could not tolerate certain foods, including cow's milk (100%), eggs (42.9%), and wheat (35.7%). Conclusions: Refractory FPIAP was protracted, with a higher incidence of growth retardation, lower hemoglobin levels, and higher corticosteroid use in the non-early onset group. The optimal treatment approach should be explored.