Risk Factors Influencing Tolerance and Clinical Features of Food Protein-Induced Allergic Proctocolitis

To examine the clinical course and risk factors of food protein-induced allergic proctocolitis (FPIAP).A total of 257 infants who presented to 5 outpatient pediatric allergy or gastroenterology clinics with rectal bleeding and were given a diagnosis of FPIAP were included in the study.After enrollment, infants had serum immunoglobulin E testing, skin-prick testing (SPT), and complete blood cell count. Clinical characteristics were prospectively managed. Patients with other known gastrointestinal illnesses were excluded. Cow’s milk elimination was trialed first in both the infant’s diet as well as the mother’s diet if breastfeeding, and, if no improvement, egg was eliminated next. Combined elimination of wheat, nuts, and soy followed, if no improvement. Eliminated foods were then reintroduced after 2 to 4 weeks, and a worsening of symptoms confirmed diagnosis.There was no sex predominance, with 50.2% being female (n = 129). The vast majority were breastfed at diagnosis (97.2%), with 66.5% exclusively breastfed. Blood in stool was present in every case, and other common complaints were mucous in stool (n = 224) and loose stool (n = 168). Cow’s milk was the most common causative food, accounting for 99.2% of cases. Comparing those with only 1 food allergy (75.9%) versus those with multiple food allergies, children with a single-food allergy more often were exclusively breastfeeding at diagnosis, had a longer duration of breastfeeding, had less antibiotic use in the first 6 months, and had higher tolerance development (P = .003, < 0.001, < 0.001, and < 0.001, respectively). Immunoglobulin E (IgE) sensitization was assessed in 239 patients, and 55 (23%) had positive test results. Sensitized children less often developed tolerance to the offending allergen compared with nonsensitized children (52.4% versus 81.2%). Only 16 patients underwent endoscopy and were continued to be treated as having FPIAP.Most patients with FPIAP resolve within a year. Infants with colic, IgE sensitization, and multiple food allergies may be at risk for delayed tolerance. Cow’s milk should be the first excluded food in infants and breastfeeding mothers, and elimination should resolve symptoms in most patients. Breastfeeding and lower antibiotic use was associated with a decrease in the development of multiple food allergies. The role of SPT and IgE testing is still unclear and may not add benefit to most cases. Endoscopy did not change management, even in severe cases.This is an important study that characterizes a common condition. The prospective nature of this study is a strength, along with high retention of subjects throughout the study. The involvement of multiple centers and specialties introduced some variability in practice. More severe cases of FPIAP are likely represented in this study because subjects had referral to allergy or gastroenterology specialists. Also, the high prevalence of breastfeeding in this cohort may limit its generalizability to other communities; regional food preferences and breastfeeding prevalence may have a large effect on the development of allergies and food sensitization.