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Food allergies are a hot topic right now. There seems to be a new food allergy every day, and many people are wondering if food allergies cause eczema. The answer is no – food allergies do not cause eczema. However, atopic dermatitis (eczema) is a risk factor for developing food allergies. In this blog post, we will discuss the relationship between food allergies and eczema. We will also look at how food-induced flaring of atopic dermatitis can occur in some children.
What is eczema?
Eczema is a chronic inflammatory skin condition. It affects millions of people worldwide, including children. Eczema is characterized by dry, itchy skin that can sometimes lead to skin infections. Atopic dermatitis is the most common type of eczema. “Atopic” means allergic. “Dermat” means skin. And “itis” means inflammation of. So atopic dermatitis is allergic inflammation of the skin. This means that the allergy components of the immune system are involved in this complex skin condition.
Most children with eczema have atopic dermatitis. Read about other forms of eczema here. For the purposes of this article, we will use eczema and atopic dermatitis interchangeably.
What are food allergies?
Food allergies are inappropriate immune responses to foods. Different types of food allergies cause different types of symptoms. The symptoms are typically determined by whether mast cells and IgE play a role in the food allergy. Food allergies can be characterized by whether IgE is involved:
IgE-Mediated Food Allergy
Non-IgE-Mediated Food Allergy
Mixed IgE- and Non-IgE-Mediated Food Allergy
How are eczema and food allergies related?
Eczema is a risk factor for developing food allergies.
In other words, people with eczema are more likely to develop food allergies than people without eczema. This is especially true for children, especially babies, with eczema.
Perhaps the most well-known research regarding food allergies and eczema was the LEAP Study. This and its follow up study LEAP On considered children to be at high risk of developing peanut allergy if they had severe eczema or egg allergy. This risk association had previously been identified in 2013. Read more about these on this prior post.
We do not know why eczema predisposes babies to developing food allergies. The thought is that the inflammation of the skin caused by eczema creates an allergic immune environment. This may happen because the skin is the immune organ that helps protect against parasite infections, and much of the same immune machinery used to prevent parasite infections is actually used in allergic reactions. If you want a deep dive on atopic dermatitis and inflammation, check out this video abstract by Dr. Lisa Beck and the video below.
Dr. Lisa Beck discusses treatment for moderate to severe eczema in children and adults.
Foods do not cause eczema.
When it comes to eczema, there are many myths and misconceptions. One of the most common misconceptions is that foods cause eczema. Food allergies do not cause eczema.
That said, some children and adults experience food-induced flaring of atopic dermatitis. What does this mean? This means that, upon ingesting a food, the baby's eczema may flare a few hours later or the next day. Many times, these children have positive skin and/or blood tests to that food. That does not mean, however, that they are necessarily allergic to the food (not allergic yet, at least!).
Here's why.
We discussed that eczema increases allergic inflammation and seems to promote allergy on a cellular, immune level. This means that many people with eczema are likely to develop IgE to lots of things: foods, pollens, etc. But just because someone has IgE to a food does not mean they are allergic.
Positive skin or blood test WITHOUT known history of allergic reaction = the patient is SENSITIZED.
Positive skin or blood test WITH known history of allergic reaction = the patient is ALLERGIC.
Allergy skin and blood tests are testing for the presence of IgE. These tests do not test for the amount of tolerance a person has to a food. Tolerance is made through a type of T cell. Currently, the only way to determine if someone is allergic to a food is through a food challenge, which should only be performed by a trained allergist. Read more about allergy testing in Dr. Hoyt's ebook all about allergy testing.
So what do you do about food-induced flaring of eczema?
It's important to see an allergist if your child has eczema, especially if you think some foods are flaring the eczema. The allergist will discuss in detail your child's history and symptoms. Skin and/or blood testing may be performed. The intention of this evaluation should be to develop a strategy to safely keep or get the food in the child's diet while improving the skin. It's important to keep foods in a kiddo's diet when at all possible so that tolerance to the food can grow. Prolonged avoidance of foods may result in allergy as was the case in the LEAP study.
Of course, if your child has had any reaction to a food, see an allergist immediately to determine next steps, and have your child avoid the food until it is determined by the doctor to be safe.
Food allergy is complicated, as is eczema. Through shared decision-making with a good allergist, these to conditions can be well managed and your kiddo and family can lead a happy, heathy life!
Are you in need of an allergist in your area? Check out these allergist finder tools:
AAAAI Allergist Finder: https://allergist.aaaai.org/find/ ACAAI Allergist Finder: https://acaai.org/locate-an-allergist
A note from Dr. Hoyt
I have talked about a non-profit…
Pam and I volunteer with the non-profit The Teal Schoolhouse. Its primary program is Code Ana. Code Ana equips schools for medical emergencies like anaphylaxis.
Code Ana’s Online Epinephrine Training Program helps support that goal. Through this program, you will educate yourself while you support this important mission!
A medical emergency response plan is important for everyone at any school. Code Ana's program Med-E Ready is a comprehensive approach to school-focused medical preparedness. This program guides schools through the process of creating a medical emergency response plan. A response team is also developed! This is one of the most important components of a school's food allergy policy!
Does your kiddo’s school have Code Ana?
You've just read Dr. Hoyt's post “Do food allergies cause eczema? Here are the facts!” Remember, she's an allergist, but she isn't your allergist, so talk with your allergist about what you've just learned!
