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

<b>Background/Objectives</b>: 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. <b>Methods</b>: 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. <b>Results</b>: 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%, <i>p</i> = 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, <i>p</i> = 0.017).The proportion of corticosteroid use was significantly lower in the early-onset group (15.0% vs. 60.0%; <i>p</i> = 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%). <b>Conclusions</b>: 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.