What is the best course of action for a 2-month-old infant with a cow's milk protein allergy who is exclusively breastfed?

Management of Cow's Milk Protein Allergy in a Breastfed Infant

The mother should continue breastfeeding and eliminate cow's milk products from her diet to manage a 2-month-old infant with cow's milk protein allergy. 1

Rationale for Continued Breastfeeding with Maternal Dietary Modification

• When a breastfed infant is diagnosed with cow's milk protein allergy, breastfeeding should be continued whenever possible, as it aligns with official infant feeding recommendations 1
• For symptomatic infants, the mother should eliminate cow's milk and dairy products from her diet, as proteins from the maternal diet can transfer into breast milk in sufficient quantities to cause allergic reactions 1
• Maternal elimination of cow's milk protein should be followed by a reassessment of the infant's symptoms, with improvement typically occurring within 1-2 weeks 1, 2

Implementation of Maternal Elimination Diet

• The mother should completely eliminate all sources of cow's milk protein from her diet, including milk, cheese, yogurt, butter, and hidden sources in processed foods 1
• A consultation with a registered dietitian is recommended to ensure nutritional adequacy of the maternal diet while avoiding cow's milk proteins 1
• The mother should be advised about calcium supplementation and other nutritional considerations to maintain her own health while breastfeeding on a restricted diet 1

Monitoring and Follow-up

• The infant should be monitored for symptom improvement, which typically occurs within 1-4 weeks depending on the type of allergic manifestation 2
• Growth parameters (weight and length) should be regularly assessed to ensure adequate nutrition 3
• If symptoms persist despite strict maternal dietary elimination for 2 weeks, consultation with an allergy specialist is recommended 1

When to Consider Alternative Feeding Options

• If the infant fails to improve despite strict maternal dietary elimination, or if the mother is unable to maintain the elimination diet, a hypoallergenic formula may be considered 1
• Options include:
  • Extensively hydrolyzed cow's milk protein formula (eHF) as first choice 3, 4
  • Amino acid-based formula (AAF) for severe cases or when eHF is not tolerated (10-20% of cases) 1
  • Rice protein hydrolysate formulas may be considered as an alternative 3, 4

Common Pitfalls and Caveats

• Avoid unnecessarily restrictive maternal diets beyond cow's milk elimination unless other food allergies are confirmed, as this may compromise maternal nutrition and breastfeeding ability 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
• Soy formula is not recommended as a first-line alternative due to potential cross-reactivity (20-40% of infants with cow's milk allergy may also react to soy) 1, 4
• Goat's and sheep's milk are not suitable alternatives due to high protein homology with cow's milk 1
• Regular cow's milk should not be introduced before 12 months of age 5

Reintroduction and Long-term Management

• Periodic reassessment is recommended, as many infants develop tolerance to cow's milk protein over time 2
• Reintroduction of cow's milk protein should be attempted under medical supervision, typically after 6-12 months of elimination 1, 2
• The timing of reintroduction may vary based on the severity of initial symptoms and should be individualized 1, 2