Baby Allergies to Formula: Causes, Symptoms, and Treatment

Has your baby recently experienced symptoms like coughing, diarrhea, or vomiting after ingesting infant formula? If so, your child may have developed an allergy to infant formula.

Read more about baby allergies to formula, including the causes, symptoms, and treatments.

What Is a Milk Allergy?

The infant formulas that are sold in stores are made from cow’s milk but have been adjusted to make the protein easier for infants to digest. Milk sugar (lactose) is added to equalize the concentration, and this ingredient is similar to that found in breast milk.

Vegetable oils and other essential fats are added to make the formula easily digestible. Other nutrients—vitamins and minerals such as iron, vitamin D, and calcium—are also added to baby formulas to meet the nutritional requirements for babies to grow.

Babies with milk allergies are allergic to the proteins in cow's milk—casein and whey. The condition is called cow's milk protein allergy (CMPA).

How Milk Allergies Affect Babies

A milk allergy (from cow's milk) is the most common food allergy in young children and infants. Many children outgrow the allergy, but some do not. Cow's milk allergy is also common among adults.

When a child has a milk allergy, the proteins in the milk stick to certain antibodies that are created by the immune system. The symptoms produced by the immune defenses that cause the reaction can be mild or severe.

Signs and Symptoms of Baby Allergies to Formula

If a baby is allergic to formula, the body overreacts to the protein in cow’s milk. The symptoms of the allergy will depend on the severity of the child's allergy. There are several signs and symptoms of a milk allergy in a baby that caregivers should be aware of.

What to Do If Your Child Has a Milk Allergy and Reacts to Formula

If your child has an allergic reaction to formula, contact your child's doctor right away—even if the symptoms are mild. At the very least, your child's doctor can help you find ways to alleviate the symptoms of a milk allergy.

If your child has a severe allergy, you might need to use an epinephrine auto-injector to treat a reaction. You'll also need to closely read ingredients on products and likely change formulas to a product that will not cause a reaction.

Diagnosis and Treatment of Milk Allergies in Infants

Your child's doctor can find out if they are allergic to milk. They will ask you questions and examine your baby. They might also want to test samples of their blood or poop.

You might be referred to an allergist—a doctor who specializes in diagnosing and treating allergies. They will ask you detailed questions about your baby's eating habits and symptoms (including how long they have been happening).

An allergist might do an allergy skin testing to milk and, if necessary, an oral food challenge. For this test, the allergist will have your baby consume a small amount of milk or milk powder, then watch to see if there is a reaction.

The doctor might also use a blood test or skin prick test to look for immunoglobulin E antibodies. For this test, the doctor will place a sample of milk on your child's skin and then prick the area to allow the substance to enter the body. If there is a reaction within 10 to 20 minutes, it indicates an allergy.  

How to Prevent an Allergic Reaction to Formula

If your baby is allergic to formula, one of the first things you'll need to do is change the formula that they are fed. Before you switch, ask your baby's doctor if they have specific recommendations.

Research has shown that breastfeeding results in fewer allergic reactions. If breastfeeding is not an option, amino acid formulas, soy formulas, and rice hydrolysates can also work for babies with milk allergies.

Summary

Infants can be allergic to baby formula. Caregivers should be aware of the signs and symptoms of a formula allergy and take steps to address the symptoms if they occur.

Diagnosing the cause of the allergic reaction is necessary to ensure that a child can be put on a feeding routine that will be nourishing and not exacerbate their allergy. If a baby is allergic to milk, there are other options for formula-feeding.

A Word From Verywell

If your baby has an allergic reaction to the formula they consume, call your child's doctor. They can figure out what is causing your child's allergy and recommend steps for you to take to keep them safe.

You might be referred to an allergist for more tests. They can also recommend specific formulas that will be a better fit for your child's needs.

Frequently Asked Questions

How do you find the right formula for a baby with allergies?

If your baby is allergic to formula, one option is to switch to breastfeeding. If that's not an option for you, there are other types of formula that can work for a baby who has a milk allergy.

What percentage of babies are allergic to formula?

Around 7% of babies who are formula-fed are allergic to cow’s milk protein, around 1% of breastfed babies are allergic to cow’s milk, and around 2.5% of children under the age of 3 are allergic to milk.

When do you stop giving your baby formula if they have allergies?

Your baby's doctor will guide you through the process of changing your feeding routine, whether you're switching to breastfeeding or a different formula. Every child is different, but you'll probably notice an improvement in your baby's symptoms within a few weeks of making the changes.