Eczema, also known as atopic dermatitis, is an allergic skin condition that is linked to food allergies, asthma and environmental allergies. It affects children more than adults. The rash is red, scaly, itchy and becomes easily infected. For mild cases, treatment with moisturizers alone can be adequate. For more severe eczema, topical steroids of varying strengths are typically prescribed, as well as non-steroids such as Elidel or Protopic, or Eucrisa.
Role of the Allergist in Managing Eczema
Allergists have special expertise in managing eczema. When eczema is chronic and poorly controlled, an allergist can help determine if there are underlying allergic causes or trigger factors that need to be identified. This may reveal allergies to foods, environmental allergens such as dust mites or pets, or sometimes a contact allergy to common chemicals. Addressing these factors may be helpful. In addition, for individuals with severe chronic eczema who are over the age of 12, use of a biologic medication such as dupilimab (Dupixent) can result in dramatic improvement with no significant side effects. Other biologic agents will become available in the future.
Increased Risk for Food Allergy
Infants with eczema are at increased risk for developing life-threatening allergies to cow’s milk, egg, peanut, tree nuts and sesame. In fact, the majority of children with anaphylactic food allergy have or have had eczema, and the more severe the eczema, the greater the risk. For this reason, any infant with significant eczema should be allergy tested between the ages of four and six months, when they are ready to start solid foods. If testing is negative for egg, peanut and tree nuts, for example, these foods should be introduced immediately in age-appropriate form, and this will markedly reduce the risk of developing food allergy.
If the testing is positive, in most cases the allergy is not severe yet. In this situation, we will usually recommend a careful introduction of small amounts of the food allergen in the office, with gradual increases over time until it is tolerated and the allergy goes away. Avoidance of allergenic foods until age two is no longer recommended anymore because it may actually result in a higher risk for developing anaphylactic food allergy in susceptible infants.
Allergic Contact Dermatitis and Eczema
A skin rash due to a chemical or plant is called allergic contact dermatitis and may have similar appearance to eczema. Examples are allergy to nickel in earrings, or to an antibacterial agent in hand soaps. A contact allergy may also develop in a person with eczema and make it difficult to treat unless the allergen is avoided. Diagnosis of allergic contact dermatitis is by “patch testing” to a panel of the most common allergenic chemicals. Once the allergen is identified and avoided, the dermatitis should resolve.