Is it a cow's-milk allergy?

Q: We think our newborn could be allergic to cow’s-milk formula. What are the signs?

A: Milk-protein allergy is a condition that develops in the first year of life. The most common form is an allergy specifically to the protein in cows’ milk. 

Symptoms — rashes, stomach upset/discomfort, vomiting and/or diarrhea — can appear within a few minutes of eating the protein, but they can also be present a few hours after consumption. 

Another symptom can be the presence of blood in the stool. Less commonly it can affect the respiratory system, causing chronic nasal stuffiness, constant runny nose, cough and wheezing. 

At the severe end of the spectrum, milk-protein allergy can cause allergic symptoms similar to those commonly associated with a severe peanut allergy, such as difficulty breathing, severe hives, swelling of the head, neck, mouth or throat areas and/or bloody diarrhea. 

If any of those symptoms occur, you should take your child immediately to the emergency room or call 911. 

Treatment for milk-protein allergy calls for removing the protein from the diet completely. 

For breastfed infants, this often means that the breastfeeding mother needs to eliminate dairy (cows’ milk) from her diet. 

For formula-fed infants, this means switching to a non-dairy based formula. 

Be aware that a high percentage of infants are sensitive to both cows’ milk proteins and soymilk proteins. For more detailed treatment recommendations, discuss your concerns with your pediatrician. 

Note: This condition shouldn’t be confused with lactose intolerance, which also typically involves dairy products (including cows’ milk). 

Lactose intolerance is a condition caused when a person doesn’t have enough of the lactase enzyme to break down or digest the sugar (lactose) in dairy products. 

Since the lactose can’t be properly digested, it then gets broken down by bacteria, which can cause gas, bloating, stomach cramps and diarrhea. 

This condition is quite uncommon in infants and younger children as people generally have higher levels of lactase in their systems in their early years.

Lactase levels, however, can decline over time, so it’s quite common to develop lactose intolerance later in life.

Kimara Gustafson is a Minneapolis mother who works as a pediatrician at Masonic Children’s Hospital and the Adoption Medicine Clinic, both at the at the University of Minnesota. Send your questions to