What Are the Symptoms of a Milk Formula Allergy?

Food allergies occur when the body’s immune system mistakes a food protein for something dangerous and attempts to fight it. This immune reaction is what causes the symptoms of an allergic reaction. Children’s Hospital Boston states that while food intolerances and allergies share common symptoms, they are not the same thing. According to the Nemours Foundation, milk allergies affect about 2 to 3 percent of babies and generally disappear by a child’s fifth birthday. Parents can prevent many allergies to milk formula by breastfeeding and delaying introduction of dairy products.

Colic and Behavioral Symptoms

In babies with a mild allergy to cow’s milk protein, colic, fussiness and irritability may be the only symptoms. Allergic infants may experience gas, bloating and abdominal cramping, and draw their legs up and cry. Irritability is typically most pronounced 15 minutes to one hour after consuming milk formula. These symptoms are often mistaken for lactose intolerance, which is an inability to digest lactose, a sugar found in dairy products.

Gastrointestinal Symptoms

Gastrointestinal symptoms may appear immediately after consuming milk formula or not until seven days after ingestion. Severe spitting up, abdominal pain, projectile vomiting and bloody diarrhea are some common gastrointestinal symptoms of a milk allergy. Blood may or may not be visible in the stool, but it is detectable with medical testing. If left untreated, gastrointestinal problems may lead to anemia, a severe rash around the anus and stunted growth, according to Children’s Hospital Boston.

Skin Symptoms

Eczema is a common reaction to cow’s milk allergy. Other skin symptoms include rashes, hives, dark under eye circles, generalized swelling, chapped lips and cracks in the corners of the mouth. Skin problems may take days or weeks to disappear, even after the infant stops drinking milk formula.

Respiratory Symptoms

An allergy to milk formula commonly causes respiratory symptoms, such as wheezing, night coughing, sinus and nasal congestion, asthma, frequent ear infections, watery eyes and runny or stuffy nose. Unfortunately, when these are the only symptoms present, the cause is often misdiagnosed as a viral infection. Dr. Alan Greene recommends consultation with an allergist when wheezing or other respiratory symptoms are present.


Anaphylaxis is a potentially fatal condition that requires emergency medical treatment, according to Keep Kids Healthy. It may develop immediately after consuming milk and causes swelling of the tongue and lips, low blood pressure, wheezing or difficulty breathing and hives. The Nemours Foundation states that anaphylaxis is less common in milk allergies than in allergies to other foods.

About this Author

Sandra Ketcham is a freelance writer and editor with more than 15 years of experience writing for both print and online publications. She specializes in health and wellness, business and travel articles and currently serves as an editor for various e-zines and company newsletters. Ketcham is currently pursuing a degree in psychology.