Yes! Even babies who are only drinking breast milk can develop food allergies.
In this case, they are allergic to a food that the mother is eating which is then passed to the baby in the breast milk. Cow’s milk allergies are the most common food allergy in breastfed babies. Manifestations of food allergies are varied but can include severe atopic dermatitis (eczema), severe reflux, and bloody stools — which get worse after a mother consumes certain foods.
Like older children with food allergies, babies can show hives, profuse vomiting, lethargy, and even have life-threatening episodes of anaphylaxis when exposed to an allergen via breast milk. Treatment is aimed at identifying which foods are causing the reaction and then completely eliminating them from the mother’s diet.
The most common food allergy in breastfed babies is the cow’s milk protein. Upon complete removal of the offending food, all symptoms should improve. True food allergies in breastfed babies are rare but if you are concerned, speak with your child’s physician before attempting an elimination diet.
Reviewed by Dr. Sara Connolly, March 2020