What formula should be used for an infant with a diagnosed Cow's Milk Protein Allergy who is currently on a normal cow's milk formula?

Management of Diagnosed Cow's Milk Protein Allergy in Formula-Fed Infants

For an infant with confirmed cow's milk protein allergy currently on standard cow's milk formula, immediately switch to an extensively hydrolyzed formula (eHF) as first-line treatment, which resolves symptoms in 80-90% of cases. 1, 2

First-Line Formula Choice: Extensively Hydrolyzed Formula (eHF)

• Switch immediately to an extensively hydrolyzed cow's milk protein formula (eHF), which is the recommended first-line treatment for formula-fed infants with diagnosed CMPA. 1, 2, 3
• The eHF demonstrates an 80-90% efficacy rate in resolving allergic symptoms within 2-4 weeks. 1, 2
• Symptom improvement typically occurs within 72-96 hours to 1-2 weeks of starting eHF. 2
• Monitor for complete symptom resolution over 2-4 weeks before confirming treatment success. 3

When to Escalate to Amino Acid-Based Formula (AAF)

If symptoms persist after 2-4 weeks on eHF, or if the infant presents with severe/life-threatening symptoms initially, switch immediately to an amino acid-based formula (AAF). 2, 3, 4

Specific indications for AAF include:

• Failure to thrive or faltering growth despite eHF treatment 4
• Severe or life-threatening initial presentation (anaphylaxis, severe enterocolitis) 2, 3, 4
• Persistent symptoms after 2-4 weeks on eHF 2, 4
• Multiple food protein allergies requiring elimination of multiple foods 4
• Severe complex gastrointestinal food allergies including food protein-induced enterocolitis syndrome (FPIES) 4
• Eosinophilic esophagitis, where AAF is first-line treatment 4
• Severe eczema unresponsive to eHF 4

Formulas to AVOID

• Do NOT use soy formula as first-line treatment due to 20-40% cross-reactivity risk with cow's milk protein. 1, 2
• Soy formula may only be considered for infants >6 months of age after establishing tolerance by clinical challenge. 1, 2
• Do NOT use partially hydrolyzed formulas, as they are inadequate for treating confirmed CMPA. 2
• Do NOT use goat's milk or sheep's milk formulas due to high protein homology with cow's milk (cross-reactivity risk). 1, 2
• Do NOT use standard cow's milk formula, which is the causative allergen. 5

Monitoring and Follow-Up

• Assess symptom resolution using a symptom-based score tracking gastrointestinal, dermatological, and respiratory manifestations. 6
• Monitor growth parameters (weight-for-age, length-for-age, weight-for-length z-scores) monthly, as children with CMPA are at risk for growth impairment. 2, 6
• Provide nutritional counseling to ensure adequate calcium and vitamin D intake, as children with milk allergy consume inadequate amounts of these nutrients. 2
• Regular growth monitoring is mandatory for all children with food allergies, particularly those with multiple food allergies who have higher risk for growth impairment. 2

Reintroduction Protocol

• Attempt supervised oral food challenge at 9-12 months of age in a hospital setting with emergency equipment available, including intramuscular epinephrine. 1, 3
• Most infants outgrow CMPA, making reintroduction attempts appropriate after 6-12 months of elimination. 3
• For IgE-mediated CMPA, ensure the patient has an epinephrine auto-injector and written emergency action plan for inadvertent exposures. 3

Critical Pitfalls to Avoid

• Do not delay switching to AAF if the infant has failure to thrive or severe symptoms persisting despite eHF. 2, 4
• Do not use soy formula as first-line due to significant cross-reactivity risk in infants under 6 months. 1, 2
• Do not use partially hydrolyzed formulas for treatment of confirmed CMPA, as they contain insufficiently broken-down proteins. 2
• Do not assume all hydrolyzed formulas are equivalent—extensively hydrolyzed formulas vary in their protective benefit and efficacy. 5
• Do not neglect nutritional monitoring, as inadequate calcium, vitamin D, and protein intake are common in children with milk allergy. 2