What is the recommended management approach for an infant with a confirmed cow's milk allergy?

Management of Cow's Milk Allergy in Infants

For breastfed infants with confirmed cow's milk allergy, continue breastfeeding while the mother eliminates all cow's milk and dairy products from her diet; for formula-fed infants, use extensively hydrolyzed formula as first-line treatment, reserving amino acid-based formula for severe cases or treatment failures. 1, 2, 3

Breastfed Infant Management

Primary Approach: Maternal Elimination Diet

• Continue breastfeeding while implementing strict maternal elimination of all cow's milk protein sources, including milk, cheese, yogurt, butter, and hidden sources in processed foods 1, 3
• Cow's milk proteins transfer through breast milk in sufficient quantities to trigger allergic reactions in sensitized infants, but not all allergic infants react to these proteins through breast milk 4, 3
• Symptoms typically improve within 1-2 weeks of maternal elimination, though improvement may take up to 4 weeks depending on the type of allergic manifestation 1, 3

Nutritional Support for the Mother

• Refer to a registered dietitian to ensure nutritional adequacy of the maternal diet while avoiding cow's milk proteins 4, 1
• Provide calcium supplementation and address other nutritional considerations to maintain maternal health during breastfeeding on a restricted diet 1, 3
• Avoid unnecessarily restrictive maternal diets beyond cow's milk elimination unless other food allergies are confirmed, as overly restrictive diets may compromise maternal nutrition and breastfeeding ability 4, 1, 3

Diagnostic Confirmation

• After 1-2 weeks of maternal elimination and symptom resolution, perform a rechallenge by reintroducing cow's milk to the maternal diet to confirm diagnosis before implementing longer periods of dietary restriction 4, 3
• This rechallenge step is critical to avoid unnecessary long-term dietary restrictions based on incorrect diagnosis 4, 3

When Maternal Elimination Fails

• If symptoms persist despite strict maternal dietary elimination for 2 weeks, or if the infant has failure to thrive, consult an allergy specialist and consider discontinuing breastfeeding in favor of hypoallergenic formula 1, 3
• If the mother is unable to maintain the elimination diet, transition to appropriate formula is warranted 1, 3

Formula-Fed Infant Management

First-Line Treatment

• Extensively hydrolyzed formula (eHF) of cow's milk protein is the first-line treatment for formula-fed infants, with an 80-90% success rate 1, 2, 5
• This recommendation is supported by the American Academy of Allergy, Asthma, and Immunology 1

Second-Line Treatment

• Amino acid-based formula (AAF) should be used for:
  • Severe reactions or life-threatening symptoms (anaphylaxis) 1, 6, 5
  • Enteropathy, eosinophilic esophagitis, or food protein-induced enterocolitis syndrome 6, 5
  • Multiple system involvement or multiple food allergies 6, 5
  • Infants who fail to respond to extensively hydrolyzed formula after an appropriate trial 1, 3, 5

Formulas to Avoid

• Soy formula is NOT recommended as first-line alternative due to 20-40% cross-reactivity risk with cow's milk protein allergy 2, 3
• Soy formula may be considered only for infants >6 months after establishing tolerance by clinical challenge 2
• Goat's milk and sheep's milk are NOT suitable alternatives due to high protein homology with cow's milk (cross-reactivity) 1, 2, 3

Introduction of Complementary Foods

• Do not delay introduction of solid foods beyond 4-6 months of age in infants with cow's milk allergy 4, 6
• Introduce supplementary foods one by one in small amounts, only after the infant is at least 17 weeks (approximately 4 months) of age 6
• Children with cow's milk-induced food protein-induced enterocolitis syndrome have a 30% likelihood of reacting to solid foods, most commonly rice or oat 2

Reintroduction Protocol

• Attempt reintroduction of cow's milk protein under medical supervision typically after 6-12 months of elimination 1, 3
• For more severe presentations, perform oral food challenge at 9-12 months of age in a hospital setting to assess tolerance development 2
• The timing of reintroduction should be individualized based on the severity of initial symptoms and type of allergic reaction 1

Critical Pitfalls to Avoid

• Do not discontinue breastfeeding prematurely when maternal elimination diet can effectively manage symptoms 1, 2, 3
• Do not implement highly restrictive maternal diets that include multiple food eliminations without confirmed allergies, as this can compromise the mother's ability to breastfeed 4, 1
• Do not recommend routine maternal dietary elimination if the infant is thriving and asymptomatic, even with a diagnosis of cow's milk protein allergy 1
• Do not use widespread skin prick tests or specific IgE tests for screening purposes, as they have poor predictive value and lead to unnecessary dietary restrictions 4
• For breastfed infants with severe eczema, optimize skin care with moisturizers and topical steroids before considering maternal allergen elimination 4

Special Considerations for Non-IgE-Mediated Allergy

• For suspected non-IgE-mediated milk allergy (such as food protein-induced allergic proctocolitis), trial a maternal cow's milk-free diet for 1-2 weeks, followed by rechallenge to assess whether symptom re-elicitation occurs 4
• Infants with non-IgE-mediated cow's milk allergy requiring maternal milk-free diets are more likely to require amino acid-based formula if trialed on formula, suggesting they are more sensitive to peptide fragments 4