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

Rationale for Continued Breastfeeding with Maternal Dietary Modification

The American Academy of Allergy, Asthma, and Immunology recommends that a breastfed infant with cow's milk protein allergy should continue breastfeeding, as it aligns with official infant feeding recommendations, and the mother should eliminate cow's milk products from her diet 1, 2
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, with improvement typically occurring within 1-2 weeks 3, 4, 5

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, and a consultation with a registered dietitian is recommended to ensure nutritional adequacy of the maternal diet while avoiding cow's milk proteins 3, 5, 6
The mother should be advised about calcium supplementation and other nutritional considerations to maintain her own health while breastfeeding on a restricted diet 5, 7

If symptoms persist despite strict maternal dietary elimination for 2 weeks, consultation with an allergy specialist is recommended, to monitor for symptom improvement, which typically occurs within 1-4 weeks depending on the type of allergic manifestation 2, 5

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, such as amino acid-based formula (AAF) for severe cases or when extensively hydrolyzed cow's milk protein formula (eHF) is not tolerated 1, 2, 8

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, and do not recommend routine maternal dietary elimination if the infant is thriving and asymptomatic, even with a diagnosis of cow's milk protein allergy 2, 5, 7
Soy formula is not recommended as a first-line alternative due to potential cross-reactivity, and goat's and sheep's milk are not suitable alternatives due to high protein homology with cow's milk 2

Reintroduction of cow's milk protein should be attempted under medical supervision, typically after 6-12 months of elimination, and the timing of reintroduction may vary based on the severity of initial symptoms and should be individualized 2, 8

For formula-fed infants, the first-line treatment is an extensively hydrolyzed formula (eHF) of cow's milk protein, which has demonstrated efficacy in clinical studies, as recommended by the American Academy of Allergy, Asthma, and Immunology 9
For infants with severe reactions or life-threatening symptoms, an amino acid-based formula (AAF) should be used as first-line treatment, according to the American Academy of Pediatrics 9

Goat's milk and sheep's milk are not suitable alternatives due to high protein homology with cow's milk, as stated by the European Academy of Allergy and Clinical Immunology 9
Discontinuing breastfeeding prematurely when maternal elimination diet can effectively manage symptoms should be avoided, as advised by the World Health Organization 9