Types of Food Allergies
Introduction
Did you know there are more than one type of food allergy? This is not something that’s commonly known and understanding the differences between the types is important when trying to decipher what may be going on with your breastfed baby.
First, let’s talk about what a food allergy is and how it differs from an intolerance or sensitivity.
Allergies are described as a hypersensitivity reaction initiated by proven or strongly suspected immunologic mechanisms, in this case food. It involves a response from the immune system and is reproduced upon exposure.
A food intolerance is when unpleasant reactions occur because someone's body lacks the substances necessary to process something. In most cases the lacking substance is a digestive enzyme. This is the case for lactose intolerance in which the person lacks the enzyme, lactase.
Food sensitivities are poorly defined but essentially involve unpleasant side effects when exposed to a certain item, but the reaction doesn’t involve an immune system response.
Types of Food Allergies
IgE Mediated
IgE mediated food allergies are the type most people think of when talking about an allergic reaction to a food. With this type of allergy, if they eat the food they are allergic to, the immune system will mount a response and release IgE antibodies against that allergen.
Symptoms of an IgE mediated allergic reaction can include:
Hives
Angioedema/swelling
Coughing
Wheezing
Runny nose/ itchy eyes
Vomiting
This type of reaction typically occurs quickly after an exposure, usually within a few minutes. IgE mediated food allergies can result in anaphylaxis, a severe, life-threatening reaction. Anaphylaxis occurs when the immune system sends the body into shock with a drop in blood pressure and narrowing of airways. Any time two systems are involved in an allergic reaction - skin and digestive, skin and lungs, etc - the person should be treated with epinephrine as this is more likely to lead to anaphylaxis.
Interestingly, IgE mediated food allergies in an infant that is consuming only human milk are very rare. This type of food allergy is much more likely to present only after solid foods are introduced.
IgE mediated food allergies can be diagnosed through skin and blood testing. In addition to testing, the allergist will take a complete history and do a thorough assessment including symptoms or reactions, in order to make the final diagnosis.
The treatment for IgE mediated food allergies is complete avoidance of the allergen and the use of epinephrine in the case of anaphylaxis.
Non-IgE Mediated
Non-IgE mediated food allergies also involve an immune response, but do not produce IgE antibodies. They are still “real” food allergies!
Symptoms of non-IgE mediated allergic reaction can include:
Vomiting
Mucous and/or blood in stools
Colic/ excessive crying
Poor growth
Rashes
Reflux
In this type of allergy the reactions are typically delayed - onset can be anywhere from a few hours to a few days.While definitely concerning and serious, a non-IgE reaction is usually not life threatening, although severe FPIES reactions can be.
It’s important to note that many times these symptoms can be the result of feeding concerns such as tongue ties or overactive letdowns, and don’t always necessarily mean there is an allergy. Additionally, with the exception of blood in the stool, it’s unlikely that when seen alone, these symptoms would indicate an allergy.
Non -IgE mediated food allergies are much more common than IgE mediated ones in an infant that is being exclusively fed human milk. Examples of non-Ige mediated allergies include food protein induced enterocolitis syndrome (FPIES) and allergic proctocolitis. I would estimate that 90% of my clients have babies presenting with allergic proctocolitis.
There is no test to diagnose non-IgE food allergies. Diagnosis is based on assessment including history and review of symptoms. However, like IgE mediated allergies, the treatment is avoidance of the allergen by the lactating parent and/or the baby.
Mixed IgE and Non-IgE
Mixed allergic conditions are those associated with a food allergy involving both IgE- and non-IgE-mediated mechanisms. Like non-IgE allergies, mixed presentations are typically delayed in onset, and occur 4 to 28 hours after ingestion of the offending food(s).
Two common conditions that are mixed IgE and non-IgE are eczema and eosinophilic esophagitis.
Conclusion
Managing allergies in your breastfed baby can be a challenging and frustrating experience. While identifying the type of allergy your baby may have doesn’t negate the difficulty of the situation, it can help with understanding the path you may be on.
Since the treatment for food allergies always includes avoidance of the triggering food, it’s important to work with a registered dietitian to ensure that your needs or your baby/child’s needs are being met. This is especially important during lactation, a time when many nutrient needs increase and diet can impact nutritional composition of breast milk.
Let me help by taking some of the frustration and confusion off your plate. Reach out to see if working with me would be a good fit.
Best,
Meghan
