Your Baby Today: New Baby, New Mom: Pediatrics 2000

Food Allergies in Babies

By Graciela Wetzler, M.D. for Your Baby Today

Food allergies in infants and babies are not very common, but they cause severe discomfort and may even be life-threatening. During the first year of life, babies may be allergic to cow's milk or soy protein present in infant formulas, and breast-fed babies may be allergic to the same protein in the mother's diet. Symptoms of milk allergies -- vomiting, diarrhea, abdominal pain, bloody stools -- may develop within minutes or hours of food ingestion. But most gastrointestinal symptoms develop over the course of days and weeks. Of greatest concern are those babies with asthma who may have difficulty breathing due to swelling of the upper airway and may have an anaphylactic reaction. Milder reactions include eczema, hives, and skin rashes. Irritability and excessive crying, which mimic infantile colic are additional symptoms. If milk allergies persist, they may inhibit the baby's growth.

Milk allergies are due to an immunological reaction against proteins called casein or whey. When allergic babies are exposed to these proteins, which may be considered foreign intruders, they become sensitized, and with each subsequent exposure the symptoms are likely to worsen. Sensitization may even occur during the last trimester of pregnancy via the ingestion of dairy products in the mother's diet, causing symptoms to develop immediately after birth.

For babies with milk allergies, a complete dietary change is necessary to avoid all products containing casein or whey. Hypoallergenic formulas are a good substitute since the milk proteins are already broken into pieces which the baby can tolerate. These formulas contain all the vitamins and iron that babies require during the first year of life. Unfortunately, these formulas do not taste good (although most infants will like them if introduced early in life) and are quite expensive. It is normal for babies who drink these formulas to have loose and foul-smelling stools, so parents should not be concerned.

For breast-fed allergic babies, I usually recommend that mothers cut out dairy from their own diet. This includes ice cream, cheese, yogurt, milk, etc. To compensate, mothers should take calcium supplements, approximately 1,500 mg per day. This regimen will allow the mother to continue to breastfeed in almost all cases.

Soy is another protein, which can cause allergic reactions, and in fact many babies who are allergic to milk have a cross-reaction to soy as well. For this reason, I rarely recommend the use of soy when babies have milk allergies. However, when hypoallergenic formulas are not available or affordable, a trial of soy formula may be recommended. Finally, parents should know that goat’s milk has the same composition as cow's milk and is therefore not hypoallergenic.

Many parents confuse milk allergies with lactose intolerance. Although it causes some of the same symptoms (abdominal pain, bloating, diarrhea) lactose intolerance is due to the lack of an enzyme necessary to digest the sugar in breast milk and formula. It may be a problem from birth, or more typically it may develop later in life. Since it is not immunologically caused, lactose intolerance is not considered an allergic reaction. Soy formulas and milk formulas without the lactose will cause the symptoms to disappear.

Many babies with milk allergies are referred to pediatric gastroenterologists when the symptoms are most severe. Diagnostic testing is often conducted to identify allergens and to evaluate anemia associated with bloody stool. Endoscopy of the large bowel will determine the source of bleeding and biopsies may be taken. Although avoidance of specific foods is the mainstay treatment, sometimes medications such as antihistamines and steroids are used for acute allergic reactions.

The good news about cow's milk and soy protein allergies is that babies outgrow these disorders by 18 months to two years of age. Milk and soy can then be reintroduced in small amounts and at regular intervals. As children get older they may become vulnerable to other food allergies, the most common being to egg, fish, peanut, and wheat. Many parents mistakenly believe that children are allergic to many foods, but the most symptoms of food allergies will improve by the elimination of only one or two foods. Unlike milk and soy, the bad news about these other food allergies is that they are usually life-long problems. For children (as well as adults) with severe food allergies, they should always have access to an Epipen (self-injectable Epinephrine) to treat unexpected life-threatening reactions.

Graciela Wetzler, M.D., is a pediatric gastroenterologist in practice at Maimonides Medical Center in Brooklyn N.Y.