A baby's entire diet starts out as milk, so it may seem impossible that a baby could be allergic to milk. Babies are not allergic to breast milk, but they can be allergic to the proteins in cow's milk and other animal milk. Only 2 to 3 percent of babies have a milk allergy, and most of them outgrow it between 3 and 5 years old, states the KidsHealth website. Some research suggests that a milk allergy is genetic, but no conclusive cause has been found.
Allergy vs. Intolerance
A milk allergy is not the same as lactose intolerance. In babies with a milk allergy, the immune system responds to a specific protein found in the milk. The immune system sees the protein as a foreign invader and responds appropriately. The Food Allergy Research and Education website explains that a lactose intolerance is an inability to digest lactose, a sugar found in milk. The immune system is not involved in babies who have an intolerance to lactose or milk protein. Milk or lactose intolerance, which is rare in babies, can cause discomfort but not life-threatening symptoms.
Symptoms of milk allergy can vary in babies according to the severity. Possible symptoms include irritability, colic, loose stools, bloody diarrhea, vomiting, spit up, runny nose, watery eyes, hives, swelling and rash. Extreme cases can result in anaphylaxis, which can cause a narrowing of the airway and restrict breathing.
Since babies can't talk, you may not know that they are suffering from some symptoms, such as upset stomach. Take note of all the symptoms you observe. For example, irritability or increased fussiness can be a sign of an upset stomach. Symptoms appear in the first few months of life, and they can appear up to a week to 10 days after ingesting milk.
Diagnosing Milk Allergy
If you suspect a milk allergy in your baby, see your pediatrician as soon as possible. Share the symptoms you've seen and your family history. Your pediatrician may then order a blood test, stool test, skin allergy test or oral challenge test to diagnose the allergy. A blood test shows the number of immunoglobulin E antibodies in the blood, while a stool test could show blood in the stool, both of which could indicate a milk allergy. With a skin allergy test, the doctor inserts a small amount of milk protein under the baby's skin with a needle. If symptoms such as a rash, hive, redness or swelling appear, your baby might have a milk allergy. With an oral challenge test, your doctor gives your baby a small amount of milk to drink in the office and monitors symptoms for several hours.
Treatment for Milk Allergy
Many babies who are allergic to cow's milk are also allergic to other types of animal milk, such as goat's milk and sheep's milk, states the KidsHealth website. Formula-fed babies may need to switch to a soy or hypoallergenic formula. If your baby is breastfed, you may need to cut milk out of your diet. Children who take milk in a cup can switch to other types of milk, such as soy, rice or almond milk. However, Dr. George Krucik writes for the Healthline website that children can be allergic to these types of milks also; work with your doctor to find the best solution. Symptoms should disappear within two to four weeks after milk is removed from the diet.