What does food allergy have to do with eczema?
This post was inspired by a recent group assignment from my FARE Certificate of Training in Pediatric Food Allergy course. This 9-month program will finish in May 2023 and provides training on up-to-date and evidence-based nutrition care for children with food allergies.
October is Eczema Awareness Month, and a good time to explore the relationship between food allergy and eczema.
The Atopic March refers to an observed progression in children from eczema or skin irritation -> food allergy -> allergic rhinitis -> asthma.
What is atopic dermatitis?
Atopic dermatitis is a chronic, inflammatory skin disorder that is characterized by dry skin and recurrent flares or pruritic eczematous rash. Pruritus is a term to describe itchiness from dry skin.
Eczema is common in young children, especially those with a family history of atopic disease. Atopic dermatitis is one of seven different types of eczema, according to the National Eczema Association. It is also the most common form of eczema.
It should be noted that eczema is not contagious. It is believed to be a result of a complex interaction between genes and environmental triggers. Symptoms of atopic dermatitis include:
Itching
Sore or painful skin
Rashes anywhere on the body
Dry and discolored skin
Poor sleep caused by itching.
What is food allergy?
So what does food allergy have to do with atopic dermatitis or eczema? A food allergy is an adverse health effect arising from a specific immune response that occurs reproducibility on exposure to a given food. Let’s break that definition down:
A food allergy is a medical condition.
It occurs when the immune system attacks a protein in food.
A reaction will be reproducible when exposed to that food. Even the smallest amount of food can cause a serious reaction.
But what about food intolerance or sensitivity? Are these the same thing as food allergy?
No. Food allergies are a medical condition involving the immune system that will be reproducible when exposed to a protein from the food. Symptoms of a food allergy reaction can range from mild (itchy mouth, hives, nausea) to severe (trouble breathing, swelling of the tongue or lips, vomiting, anaphylaxis).
A food intolerance occurs when the digestive system is unable to break down or digest a certain food. A common example is lactose intolerance.
There is no consensus definition from the allergy community for food sensitivity, which makes it so confusing to differentiate.
But only food allergy involves the immune system. The only way to prevent a food allergy reaction is careful and complete avoidance of that food. This is different from managing a food intolerance or sensitivity, where small amounts of the food can often be eaten safely.
What does food allergy have to do with eczema?
Eczema is a skin condition, but it can be a risk factor for developing food allergies. Nearly 40% of children with moderate to severe atopic dermatitis (the most common form of eczema) have clinically significant IgE-mediated food allergy.
Children with eczema are at a higher risk for food allergies than those without. So should every child with eczema be tested for food allergies?
The consensus is no. For starters, both skin prick testing and serum specific IgE testing (blood draws) both have high false positive rates. This means many people without clinical food allergy will have positive tests.
Many allergists will advocate that patients DO NOT remove food from their diet based on testing alone. These allergists will also rely heavily on a detailed history when determining if someone actually has a clinical food allergy.
Unnecessary food avoidance in those without clinical food allergy can have negative consequences:
Reduced quality of life
Delay in diagnosis for underlying condition
Possible immune consequences, including the actual development of clinical IgE-mediated food allergy
Ultimately, many allergists will only recommend allergy testing after exploring skin care and topical treatment for eczema. They may consider food allergy testing in patients with moderate to severe atopic dermatitis when optimal skin care does not improve their symptoms. And of course, those with a clear history of food allergy reaction should be evaluated.
Here are some skin care recommendations for atopic dermatitis from the American Academy of Dermatology Association (AAD):
Bathe child in warm (not hot) water
Limit bath time to 5-10 minutes
Use soap that is mild and fragrance-free
Avoid bubble baths
Gently pat skin partially dry after bathing
Apply medication (if prescribed) when skin is almost dry and use medication as directed
Place moisturizer (thick cream or ointment work best) on top of the medicine and to the rest of child’s skin.
Additional recommendations are available on the AAD website.
More information and additional resources:
As a dietitian, I do not offer any testing for food allergies or sensitivities. I can help with creating a clear and detailed diet history or nutrition education following a food allergy diagnosis.
However, I do strongly encourage individuals and parents concerned about food allergies to request a referral to a qualified Allergist.
You can use this search tool to find an allergist in your community. It is available from Food Allergy Research & Education (FARE), in partnership with the American Academy of Allergy, Asthma & Immunology (AAAAI) - the professional society for allergies or asthma. Please note that not all allergists specialize in food allergy, so contact the provider office in advance to determine if they can help meet your needs.
And ultimately, this blog post is only the evidence-based opinion of one dietitian. For more reading on the relationship between eczema and food allergies, please visit these credible websites:
