BOSTON – Between 15% and 30% of children with moderate to severe atopic dermatitis also have food allergies, but the allergies are a trigger for AD in only a small subset of patients, according to Mercedes E. Gonzalez, MD.
In most cases, allergy testing is not indicated, she said at the American Academy of Dermatology summer meeting.
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She described a scenario involving a parent who is concerned that a food allergy is causing her child’s AD. The child has had no hives, no lip swelling, and no other signs of immediate hypersensitivity. In such a case, the best approach is to treat with topical therapies and follow the patient clinically.
“Allergy testing independent of history is not recommended,” she said.
However, in cases involving a significant concern about food allergy, such as the presence of hives or urticaria, or when the child has severe dermatitis that is not improving with optimized topical therapies, an assessment can be undertaken, said Dr. Gonzalez of the University of Miami.
She recommended limited food allergy testing – for common culprits such as cow’s milk, eggs, wheat, soy, and peanuts – in children younger than age 5 years with moderate to severe AD, if the AD persists despite optimized topical treatment and/or a history of immediate and reproducible reaction after ingestion of a specific food.
Food elimination diets based solely on the findings of food allergy test results are not recommended for managing AD, she noted.
If a patient has true immunoglobulin E–mediated allergy they should practice avoidance to prevent potential serious health sequelae, Dr. Gonzalez said.
When testing is done, keep in mind that skin prick tests and serum-specific IgE levels have high negative predictive values above 95%, but low specificity and positive predictive values of 40%-60%, she pointed out. Positive tests should be verified with a food elimination diet or oral food challenge.
Also, most children develop tolerance to the foods over time and should be retested, Dr. Gonzalez said.
Early peanut introduction advised in infants with AD
There is no need to delay the introduction of peanuts into the diet of an infant at high risk for atopic dermatitis, Dr. Gonzalez said.
A 2015 consensus communication from the American Academy of Pediatrics and numerous other organizations, including the American Academy of Allergy, Asthma & Immunology and the Society of Pediatric Dermatology, offering interim guidance on the topic calls for introduction of peanut products into the diets of high-risk infants in countries where peanut allergy is present, she said.
High-risk infants were defined in the study as those with egg allergy and/or severe eczema.
The guidance, which the AAP “endorses and accepts as its policy” pending more formal guidelines currently in development, was based largely on findings from the LEAP (Learn Early About Peanut Allergy) trial – a 5-year randomized, controlled trial of 640 high-risk infants aged 4-11 months. The trial showed that 17.2% of infants who avoided peanuts had peanut allergy at 5 years, compared with 3.2% of those with peanut consumption three times weekly, a relative risk reduction of 81% (N Engl J Med. 2015; 372:803-13).
In infants with egg allergy or severe eczema, an evaluation by an allergist or dermatologist familiar with the guidance may be warranted to assist in implementing the suggestions, Dr. Gonzalez said.
Dr. Gonzalez reported receiving honoraria for serving as a speaker and/or advisory board member for Pierre Fabre Dermatologie, Anacor Pharmaceuticals, Encore Dermatology, and PuraCap Pharmaceutical.