Snapshot An infant girl is brought to the pediatrician by her parents due to finding blood in her diaper. This began approximately 2-3 days prior to presentation and has not happened before. Her stools have become loose and streaked with blood. She is exclusively breastfed every 3 hours and voids approximately 10 times a day. The mother's diet consists of fish, fruits, vegetables, nuts, and milk. On physical examination, the infant is healthy-appearing and cooing. There are no anal fissures and her stool is loose with streaks of blood mixed in. Introduction Clinical definition infant distal colon inflammation secondary to an immune reaction to certain food proteins which results in rectal bleeding Epidemiology Incidence a common cause of rectal bleeding in infants who are breastfed and formula-fed Demographics almost exclusively in infants Dietary triggers include cow's milk soy egg ETIOLOGY Pathogenesis not an IgE-mediated immune reaction to the distal rectum IgE-mediated immune reactions are seen in classical food allergies which present with a rapid onset (minutes to two hours) skin, respiratory, gastrointestinal, and/or cardiovascular involvement Presentation Symptoms passing of blood-tinged stools and mucus but is otherwise healthy may be fussy, have increased frequency of bowel movements, and have eczema Physical exam typically stools are soft and loose have blood specks/streaks within the stool may have mucous Differential Anal fissures stools are typically firm with streaks of blood found on the outside Necrotizing enterocolitis Intussusception Enteric infection Meckel's diverticulum DIAGNOSIS Diagnostic criteria this is a clinical diagnosis based on having an otherwise healthy infant with small amounts of rectal bleeding confirmation after symptom resolution secondary to removal of the presumed food antigen Treatment Conservative modifying the mother's diet indication breastfed infants in whom the mother's diet contains the suspect food e.g., eliminating cow's milk from the mother's diet outcomes breastfed infants typically respond to this maternal dietary modification hydrolyzed formula indication used to replace cow's milk or soy-based formula in formula-fed infants Complications Persistent food allergy rare Chronic colitis rare Prognosis Excellent because almost all infants are able to tolerate cow's milk and soy products by the time they become one year of age