Prospective Assessment of Pediatrician-Diagnosed Food Protein-Induced Allergic Proctocolitis by Gross or Occult Blood

Abstract

Background: Food protein-induced allergic proctocolitis (FPIAP) is an early and common manifestation of food allergy, yet its epidemiology and relationship to other allergic diseases remain unclear.

Objective: To prospectively define the incidence of FPIAP as it is being diagnosed clinically in the community and to identify factors associated with its development.

Methods: A total of 1003 of 1162 eligible serial healthy newborn infants recruited from a single suburban pediatrics practice were followed prospectively for the diagnosis of FPIAP. Investigators reviewed each case to confirm prespecified inclusion criteria, including documented gross or occult blood in the stool.

Results: A total of 903 infants were analyzed (46% females, 89% term, 32% caesarian-section, 9% neonatal antibiotics); 153 cases met inclusion criteria, a cumulative incidence of 17%, while 63 (7%) had gross blood. Infants initially fed both breast milk and formula were 61% less likely to develop FPIAP compared with those exclusively formula-fed (hazard ratio, 0.39; P = .005). Breast milk and formula at any point during the first 4 months were also associated with lower risk compared with exclusive formula or exclusive breast milk (hazard ratio, 0.44; P = .005; hazard ratio, 0.62; P = .0497). Eczema (odds ratio, 1.5; 95% confidence interval, 1.1- 2.2; P = .02) or a first-degree relative with food allergies (odds ratio, 1.9; 95% confidence interval, 1.2-2.8; P = .005) were among risk factors for FPIAP development.

Conclusions: The prospectively defined incidence of FPIAP when diagnosed clinically by community pediatricians without challenge is markedly higher than published estimates. Combination feeding of formula and breast milk is associated with the lowest rate of FPIAP in this population.

Keywords: Cow's milk protein allergy; Food protein–induced allergic proctocolitis; Non–IgE-mediated milk allergy.

Figure 1.. Study population and follow-up.

*there were 6 subjects who met more than one of the analysis exclusion criteria

Figure 2.. Early life risk factors for FPIAP development.

*denotes hazard ratio reference group for polytomous variables. Reference group chosen was the largest by default, except for infant initial diet for which, given our a priori hypothesis that any breastmilk would be protective, formula is the appropriate reference.

Figure 3.. Effect of infant diet on FPIAP development.

(A) Kaplan-Meier curves of time to FPIAP diagnosis by infant initial diet. (B) Kaplan-Meier curves of time to FPIAP diagnosis by infant diet as a time-varying covariate over the first four months (during which 95% of FPIAP cases presented).