Foods that Trigger or Improve Atopic Dermatitis
The big idea:
Food allergies can trigger or worsen atopic dermatitis (eczema), particularly in infants and children with severe cases. This is distinct from Systemic Contact Dermatitis (SCD), which occurs when consuming food antigens or additives causes an immune-mediated allergic reaction in individuals sensitized through the skin or gut.
What the study asked:
The study aimed to explore:
If food can actually trigger or worsen the condition of atopic dermatitis, and
What some of the most common food allergens that trigger atopic dermatitis are, and how we can detect them.
Explanation of key terms:
Systemic contact dermatitis (SCD):
Occurs when a person who is already sensitised to a substance through skin contact is exposed to that substance (allergen) via a systemic route (uptake of an allergen).
Allergic contact dermatitis:
Occurs due to external allergen exposure that results in a local inflammatory response at the site of skin contact.
What the study did:
The study analysed the relationship between atopic dermatitis and systemic contact dermatitis, and reviewed available diagnostic and treatment strategies.
What the study found:
Relationship with food allergies:
One study of children with severe AD demonstrated that when foods triggering immediate reactions were eliminated from the diet, AD improved.
Food elimination diets may be helpful in a subset of patients with AD, but they must be recommended with caution and only in specific cases.
The expert panel recommends avoidance of the specific food allergens in cases of documented food allergies concurrent with AD.
In the absence of documented food allergies, dietary restrictions are not advised for patients with AD, as no evidence exists to suggest reduction of symptom severity.
Diagnostic tests:
The gold standard for diagnosis remains the double-blind, placebo-controlled food challenge, in which the suspect food and placebo are administered in the clinic or hospital setting.
Common triggers of SCD:
Balsam of Peru (BOP) (type of resin)
Includes chemicals such as cinnamates and vanillin that are related to or are found in flavourings, spices, and certain foods.
Major related foods to avoid include citrus fruits, tomatoes, and certain spices.
Since spices, such as cinnamon, vanilla, and cloves, are related to BOP, patients must be careful with baked goods, certain condiments, and certain liquors.
Other potential triggers include chocolate and colas.
Nickel
Foods that are higher in nickel include certain grains, including whole wheat bread and oatmeal.
Vegetables that are higher in nickel content include beans, lentils, peas, soybeans and soy products, and some canned vegetables.
Shellfish, processed meats with fillers, and canned meats or fish are also included.
Other sources of dietary nickel include chocolate, nuts, seeds, black tea, and canned foods in general.
Propylene glycol (found in artificial food products)
Found in salad dressings, barbecue sauce, snow-cone mixes, food colourings, and sour cream.
What this means for eczema:
Atopic Dermatitis VS Systemic Contact Dermatitis:
In patients with AD, food allergens may lead to the worsening of dermatitis, while in patients with SCD, food allergens may be the cause of the dermatitis.
In selected patients with AD, avoidance of specific dietary allergens has resulted in improvement of signs and symptoms of chronic dermatitis. However, in patients with SCD, avoidance of allergens, as identified by patch testing, has resulted in resolution of the dermatitis.
Increased awareness of potential food triggers, in conjunction with the appropriate diagnostic testing, can facilitate early identification of allergens, thus reducing the morbidity associated with chronic dermatitis and improving quality of life.
Link to study:
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