Clinical Features and Clinical Course of Food Protein-Induced Allergic Proctocolitis: 10-Year Experience of a Tertiary Medical Center

J Allergy Clin Immunol Pract. 2022 Jun;10(6):1608-1613. doi: 10.1016/j.jaip.2022.02.013. Epub 2022 Feb 22.


Background: Food protein-induced allergic proctocolitis (FPIAP) is a food allergy characterized by bloody stools in well-appearing breast-fed infants.

Objective: To determine the clinical course of FPIAP and the factors affecting the development of tolerance.

Methods: Over a 10-year period, patients with a diagnosis of FPIAP who were followed at the outpatient Allergy-Immunology clinic in a tertiary care children's hospital in Turkey were retrospectively analyzed.

Results: The frequency of FPIAP was 0.18% among 64,549 patients. The median age of symptom onset was 2 months (interquartile range, 1.0-3.5 months), and the median age of tolerance development was 12 months (interquartile range, 8.0-17.21 months). The occurrence of symptoms in the neonatal period was associated with a history of premature birth (odds ratio, 3.75; 95% CI, 1.33-10.59; P = .031) and neonatal intensive care unit hospitalization (odds ratio, 4.72; 95% CI, 1.78-12.53; P = .002). Use of a cow's milk-based formula was associated with a higher risk of the onset of symptoms after 1 month (odds ratio, 2.69; 95% CI, 1.19-6.07; P = .016). The use of an amino acid-based formula and the presence of diarrhea at admission were associated with later development of tolerance (P = .023 and P < .001, respectively). An IgE-mediated reaction was observed during oral food challenge testing in 6% of the patients.

Conclusions: The manifestations of FPIAP appeared earlier in premature infants and later in infants using formula. The use of amino acid-based formula and having had diarrhea were associated with delayed tolerance.

Keywords: Bloody-mucus stool; Diarrhea; Food protein–induced allergic proctocolitis; Infant; Tolerance.

MeSH terms

  • Allergens
  • Amino Acids
  • Animals
  • Cattle
  • Diarrhea / epidemiology
  • Female
  • Food Hypersensitivity* / diagnosis
  • Hospitals
  • Humans
  • Infant
  • Milk
  • Milk Hypersensitivity* / diagnosis
  • Milk Hypersensitivity* / epidemiology
  • Proctocolitis* / complications
  • Proctocolitis* / diagnosis
  • Proctocolitis* / epidemiology
  • Retrospective Studies


  • Allergens
  • Amino Acids