When your baby has food allergies it can stir up a whirlwind of information. Or maybe it feels like a lack of information! It’s a stressful time that you want to fix– fast.
There are many factors at play when it comes to infant food allergies. First, it’s very important to differentiate infant food allergies versus infant food intolerances.
According to the American Academy of Allergies, Asthma, and Immunology (AAAAI), infant food intolerances occur when the digestive system cannot break down certain foods.  This can be caused by food sensitivities or enzyme deficiency. Read more about types of enzymes and tests here, as enzyme deficiencies can be tested for.
Infant food intolerances can still cause many concerning symptoms such as eczema, vomiting, diarrhea, and bloody stools. Luckily, most infants grow out of their intolerances.
AAAAI states that infant allergies cause the immune system to overreact as though something is invading the body. One type causes an overproduction of antibodies called immunoglobulin E (IgE). Having IgE antibodies in excess causes an allergic reaction.  These are called IgE allergies.
Another type of allergic reaction occurs without producing IgE antibodies but still alarms the immune system. For this exact reason, they are called Non-IgE allergies. Non-IgE allergies are the most common offender for infant reactions to proteins in breast milk or solids.
Below we’ll further discuss these two categories of infant food allergies: IgE and Non-IgE. Non-IgE also has subcategories that we’ll touch on.
The Basics of IgE-Mediated Infant Food Allergies
The immune system is very complex and works to protect our bodies against bacteria, viruses, and more. In the case of food allergies in infants, the immune system is triggered by food proteins that enter through breast milk or solids.
We know that a breastfeeding mother passes food proteins to her baby while nursing. Sometimes the immune system disagrees with certain food proteins. This causes an allergic reaction causing the body to go into overdrive, fighting off the “invader” by creating IgE antibodies.
Overproduction of IgE antibodies causes an allergic reaction that can involve the lungs, eyes, mouth, intestines, brain, heart, or skin and range from mild to life-threatening. IgE-mediated food allergy is a leading cause of anaphylaxis, a severe, potentially fatal allergic reaction presenting to emergency departments. 
IgE allergies are the scary ones you think of when someone eats a peanut and then all of a sudden can’t breathe. It’s terrifying to think of this happening to your baby.
The most common IgE-related allergens in infants are milk, soy, eggs, peanuts, tree nuts, and wheat. Finding out if your baby has an IgE allergy can be a challenge. Skin prick tests or blood tests are not commonly performed until the baby is at least 6 months, as results are often inaccurate at younger ages. 
A recent study in 2018 about skin prick testing states “caution should be made when interpreting results and only suspected food allergens should be tested since food skin testing has a low specificity.” 
It can take time and a lot of patience to figure out IgE allergies in your baby. Stay strong and work with your baby’s doctor by providing a detailed history of previous reactions and symptoms.