Soy can cause an allergic reaction in some babies who are exposed to foods containing it. Because no one knows specifically what causes a soy allergy to develop, it isn't possible to prevent allergies from developing. Understanding the signs of a soy allergy and what to do about it can help you recognize and deal with the problem if it occurs in your child.
Causes
Soy allergies in a baby develop when her immune system responds to the proteins in soy by mounting an overblown immune response. Part of this response involves the release of histamines, which can invoke allergy symptoms all over the body. There are at least 15 soy proteins that can act as allergens. Allergies in a baby may develop when the infant begins eating solids, but they can occur earlier in some cases. If you are breastfeeding your baby, she may develop an allergy through soy proteins that have made their way into your milk. A formula-fed baby may develop an allergy to a soy-based formula.
Symptoms
The symptoms of an allergy to soy is often milder in babies than a cow's milk or nut allergy, but many of the same symptoms still occur when he consumes soy products or soy-based formula. The baby may develop a red rash around his mouth or itchy red bumps on the skin. The face, legs or arms might swell. The baby might cough, wheeze or have difficulty breathing. He might become nauseated, vomit or develop diarrhea. In severe cases, the baby may have a potentially deadly anaphylactic reaction. Not all babies have the same symptoms, and some infants have a more severe reaction than others. Symptoms often do not develop the first time a baby is introduced to soy, but only begin after subsequent exposures.
Solution
If you determine that your baby has a soy allergy, the first step is to eliminate the source of soy in the diet. If your baby develops the allergy in response to soy formula, discuss with her doctor whether to try a hypoallergenic formula or cow's milk-based formula if she is not also sensitive to dairy. Mothers of breastfed babies may need to eliminate soy from their own diet until the baby is older or fully weaned. For babies with a severe soy allergy, the doctor will typically give the parents a dose of injectable epinephrine to carry with them at all times in case the baby is exposed to soy.
Considerations
While there is no sure way to prevent food allergies, including allergies to soy, exclusive breastfeeding for six months before introducing solids may help reduce the risk. Because soy proteins can be present in other foods, read labels carefully before introducing new food items to your baby. Babies frequently outgrow soy allergies by the age of 3, so your child may be able to tolerate tofu, soy milk and other soy foods as he ages.
