A Prospective Assessment of Clinical Characteristics and Responses to Dietary Elimination in Food Protein-Induced Allergic Proctocolitis.

Background: Some aspects of diagnostic elimination/challenge diets in food protein-induced allergic proctocolitis (FPIAP) are still poorly defined.

Objective: This study investigated the symptom spectrum, time required for resolution of each symptom, triggering foods, and risk factors for multiple food allergies (MFA) in FPIAP.

Methods: Infants referred with visible blood in stool were enrolled after etiologies other than FPIAP had been excluded. Laboratory evaluation, clinical features, and elimination/challenge steps were performed prospectively during diagnostic management.

Results: Ninety-one of 102 infants (53 boys) were diagnosed with FPIAP. Eleven children did not bleed during challenges. Visible blood in stool began before 2 months of age in 63.6% of the infants not diagnosed with FPIAP, compared with 18.9% of the patients with FPIAP (P = .003). Offending foods were identified as cow's milk (94.5%), egg (37.4%), beef (10.9%), wheat (5.5%), and nuts (3.3%). MFA was determined in 42.9% of patients. Multivariate logistic regression analysis identified atopic dermatitis (AD) (odds ratio [OR]: 2.98, 95% confidence interval [CI]: 1.18-7.55, P = .021) and an eosinophil count ≥300 cells/μL (OR: 2.72, 95% CI: 1.09-6.80, P = .032) as independent risk factors for MFA. Blood and mucus in stool disappeared in a median 3 days (interquartile range [IQR]: 1-14.5 days) and 30 days (IQR: 8-75 days), respectively.

Conclusions: A tendency to transient bleeding occurs in infants who present with bloody stool before 2 months of age. A 2-week duration of elimination for blood in stool is sufficient to reach a judgment of suspected foods for FPIAP. Mucus in stool is the last symptom to disappear. Concurrent AD suggests a high probability of MFA in FPIAP.