Eczema and food allergy frequently coexist in children. Eczema also known as atopic dermatitis, is a chronic inflammatory multifactorial disease with a relapsing course. Worldwide, approximately 5-20% of children are affected by eczema, causing a significant reduction in quality of life for children and their families. We have written about eczema extensively in previous blog posts.
Several factors suggest a role for IgE (allergy) in the role of atopic dermatitis. Atopic dermatitis is usually the first manifestation of the atopic march or atopic triad. Children are at a greater risk for developing allergic rhinitis or asthma later in life. Eczema is associated with an increase in specific IgE to foods, which is often detected in early childhood. In general, the more severe the atopic dermatitis, the higher prevalence of food allergy. Children with mild eczema are often not considered to be at significant risk for food allergy; therefore it is usually not recommended to perform allergy testing in these patients.
Three different clinical reactions have been reported in patients with eczema.
- Immediate-type reactions which commonly occur within 2 hours after ingestion of food, such as hives, swelling or respiratory symptoms.
- Itching, occurring within 2 hours after the ingestion of food with subsequent scratching leading to worsening of atopic dermatitis.
- Late reactions have also been described, a flare of atopic dermatitis usually after 6 to 48 hours.
An article published in the Annals of Allergy Asthma and Immunology in April 2016 looked at the association of food allergy and eczema (atopic dermatitis) exacerbations. The authors studied over 1000 children and the conclusion they came up with was that children with eczema are more frequently sensitized to foods. They suggest that children with atopic dermatitis should be considered for testing.
The practical implications is that children who have moderate to severe eczema should be evaluated for food allergies as they may play a role in their exacerbations. An allergist can evaluate what the food allergy triggers are, the most common foods are milk, wheat, soy, eggs, peanuts, nuts, fish and shellfish.
For more information on atopic dermatitis, see the link below.