Babies are not born with food allergies, they develop over time. A food allergy occurs when your child's immune system decides that a food is a "danger" to your child's health. Your child's immune system sends out immunoglobulin E (or IgE) antibodies that react to the food and cause the release of histamines and other chemicals i.e. an allergic reaction.
The #1 risk factor and the most common way food allergies can happen is when a baby with eczema gets introduced to new foods through their broken-down skin, instead of through their mouth and tummy. Another way food allergies happen is when a baby eats a new food. In both cases, their immune system can mistakenly treat proteins found in food as a threat.
Somewhat incredibly, 70% of your baby's immune cells reside in the lining of her stomach and GI tract. Consistently exposing your baby's tummy to a food helps train her immune system to see this food as food, rather than as a threat or an allergen.
Signs of food allergy in infants are unusually immediate or within minutes (and no more than 2 hours) of eating. For babies, the most common allergic reaction consistent with a food allergy is development of hives on the skin, and/or vomiting. Other mild to moderate symptoms include swelling of the face, lips, and eyes.
Confirmation of a food allergy comes with allergy testing from a pediatric allergist if a parent and/or pediatrician are concerned about reactions from food after eating. Unfortunately all babies are at risk for developing food allergies today more than ever before; nearly 320,000 babies born this year will go on to develop a food allergy before they go to college if current rates of allergies hold. We want parents to feel confident introducing new foods to their babies, but also be prepared by knowing the signs of a possible allergic reaction and what to do if your baby does react to a food.
If your baby shows any signs of an allergic reaction: