Soy allergies are among the most common food allergies in children. Often discovered when a child has a reaction to a soy-based formula, most reactions are mild but in rare cases can result in a life threatening reaction known as anaphylaxis. While avoidance of soy and soy based products is the only treatment, most children outgrow soy allergies by the age of 3.
Background
An allergy to soy protein is a result of an aberrant immune system response to the protein. Your child's immune system erroneously identifies the soy protein as potentially harmful and forms antibodies known as IgE, or immunoglobulin E. The next time your child encounters soy protein, these antibodies recognize the protein and initiate a cascade of events that ultimately results in the release of chemicals into his bloodstream that produce the symptoms of an allergic reaction. These symptoms may be mild and can include a skin rash, hives and swelling. More systemic symptoms can occur as well, including a cough, shortness of breath, difficulty talking, vomiting and dizziness or a loss of consciousness. An allergic reaction that produces these systemic symptoms can be life threatening and is called anaphylaxis.
Diagnosis
Your child's physician can determine whether an allergy to soy protein is likely by discussing your child's symptoms with you. If your child develops symptoms consistent with an allergic reaction within minutes to an hour after ingesting food that contains soy protein, soy may be the cause of the reaction. Skin testing, which involves scratching the surface of your child's skin with the allergenic protein and then measuring the resultant reaction, can be performed in a physician's office. Blood testing that measures the level of IgE antibodies to soy protein can also be checked to determine whether a soy allergy is likely.
Avoidance
If your child is drinking infant formula, switching from a soy based to a milk protein based or elemental formula will be necessary. If you are breastfeeding, you will need to eliminate all soy protein from your diet and your child will need to eliminate soy protein from any solid foods he is consuming. Soy can be a base for sauces, grits, nuts, milk and flour and can be found in foods such as vegetable broth, vegetable gum and flavorings. You will need to check all food labels to determine whether soy protein is an ingredient.
Treatment
If your child is diagnosed with a soy allergy, your physician will go over an action plan that details the steps that you should take in the event of an accidental exposure. For minor skin reactions, your physician may suggest that your child take an over-the-counter antihistamine to relieve the symptoms of itching. For a more systemic reaction, your child will carry injectable epinephrine to quickly reverse the allergic reaction. If injectable epinephrine is needed, you should call for an ambulance so that your child can be examined and ensure that no further therapy for the reaction is indicated. Your action plan will be tailored specifically for your child and an allergist should discuss potential symptoms and treatments with you.
