Tuyet A. Nguyen, BS and Lawrence F. Eichenfield, MD
Rady Children’s Hospital, San Diego
What is a food allergy?
· A food allergy is defined as certain effects on health that happen reproducibly on exposure to a given food. These are due to an immune response from the body.
· A positive allergy test is not the same thing as having an allergy. Sometimes tests are positive, but no reaction happens when the food is consumed. This can make diagnosis of food allergies difficult.
How do food allergies present?
Food allergies can lead to:
- Skin: redness, itchiness, hives, swelling, or a rash
- Respiratory: nasal congestion, runny nose, sneezing, hoarseness, cough, chest tightness, shortness of breath, wheezing
- Gastrointestinal: swelling of the lips, tongue, or palate, nausea, abdominal pain, reflux, vomiting, diarrhea, bloody stools
- Cardiovascular: increased heart rate, low blood pressure, dizziness, fainting, loss of consciousness
What’s the risk of developing food allergies if I have AD?
- Children with AD have a higher risk of developing food allergies. In the general population, the risk of developing food allergies is 1-3%. In children with AD, the risk of developing food allergies is 10-20% with milder AD and up to 40% with severe AD.
Can food allergies make my AD worse? How do I know if food allergies are a trigger?
Food allergies can cause sometimes flare-ups or worsening of AD symptoms.
Food allergies in children with AD can present with:
- Immediate-type reactions such as anaphylaxis, hives, redness, itchiness, or swelling (or gastrointestinal, respiratory, or cardiovascular symptoms) without exacerbations of AD.
- Itchiness caused by ingestion of certain foods with subsequent scratching leading to exacerbations of atopic dermatitis.
- Late reactions which present as exacerbations of AD occurring 6-48 hours after ingestion of a food.
Should I be tested for food allergies?
- Currently, the National Institute of Allergy and Infectious Diseases (NIAID) recommends screening in kids with AD if there is:
(1) AD in the setting of a positive food reaction on consumption OR
(2) Severe AD that is not responsive to treatment
How do you diagnose food allergies?
The diagnosis of food allergy ALWAYS involves:
- Complete history (including diet, history of urticaria, respiratory symptoms, gastrointestinal symptoms, or anaphylaxis with food exposure or consumption)
- Physical examination
The diagnosis of food allergy MAY involve:
- Allergy testing (skin prick test or food allergen specific IgE)
- Oral food challenges in a structured medical setting
- Food elimination diets
How do I manage food allergies and AD?
Food allergies may or may not make your AD worse.
The principles of treatment in children with AD with food allergy are generally the same as without food allergy, and skin directed therapy should remain the initial approach focusing on:
- (1) Maintenance skin care
- (2) Topical anti-inflammatory medications
- (3) Itch control
- (4) Managing infectious triggers
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