Cow's milk protein allergy (CMPA) is often evoked in infants, in particular in front of delayed symptoms such as rectal bleeding, atopic dermatitis, excessive crying, reflux, failure to thrive... But in case of non IgE-mediated CMPA, the only way to diagnose this allergy is to proceed to an elimination-reintroduction test over a period of 2 to 4 weeks, to improve symptoms first, and then provoke them. Even if the diagnosis is confirmed, we speculate that non IgE-mediated CMPA has a faster resolution than other CMPA.

The first aim of this study is to estimate the prevalence of non IgE-mediated CMPA in a cohort of infants with delayed symptoms which could be relied to a CMPA. The second goal is evaluate the age of tolerance in non IgE-mediated CMPA with oral food challenge for milk ever 2 months after 4 months of age.

Inclusion Criteria:

• infants under 4 months age with delayed symptoms evoking CMPA

Exclusion Criteria:

• exclusively breastfed infants
• no improvement of symptoms despite amino acid formula
• patients with symptoms of food protein induced enterocolitis
• patients who do not have diagnostic oral food challenge within 3 months after the start of elimination diet

All infants under 4 months of age consulting for delayed symptoms evoking CMPA are prospectively included. All these infants benefit from a CMP elimination diet by replacing their usual formula with an extensive CMP hydrolysate, hydrolysed rice-protein formula, or an amino acid-based formula (AAF). Only children whose symptoms disappear after this exclusion diet are selected for the study.