Table 3 Proposed diagnostic criteria for FPIES, AP and FPE [2]

1. < 2 years of age at first presentation (frequent but not mandatory)

2. Exposure to inciting food elicits repetitive and projectile vomiting, pallor, lethargy within 2–4 h; symptoms last a few hours, usually resolve within 6 h; diarrhea may be present, much less frequently and later (5–10 h)

3. Absence of symptoms that may suggest an IgE-mediated reaction

4. Avoidance of offending protein from the diet results in resolution of symptoms

5. Re-exposure or OFC elicits typical symptoms within 2–4 h; two typical episodes are needed to establish the definitive diagnosis without the need to perform an OFC

1. Small amount of rectal bleeding in an otherwise healthy infant

2. Disappearance of symptoms after all antigens are removed from diet

3. Exclusion of other cause of rectal bleeding

1. < 9 months of age at initial diagnosis

2. Repeated exposure to causative food elicits GI symptoms without alternative cause, predominantly vomiting and failure to thrive

3. Confirmation of the diagnosis by small bowel biopsy in a symptomatic child, showing villous injury, crypts hyperplasia, and inflammation

4. Removal of causative food results in resolution of symptoms within several weeks, although complete healing of villous injury may take several months