ATOPIC DERMATITIS

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ATOPIC DERMATITIS

Key points:

1. Prenatal followed by postnatal probiotic supplementation decreases the risk of atopic dermatitis in new borns.

2. Postnatal prebiotic supplementation decreases the risk of atopic dermatitis

3. Elimination diets are only appropriate for patients who have a food allergy that has been proven by oral food challenge

4. Maternal allergen avoidance diets do not prevent atopic dermatitis

5. Exclusive breastfeeding and supplementation with hydrolyzed formula is protective against atopic dermatitis for high-risk infants

6. For infants at normal risk, breastfeeding is not protective for atopic dermatitis

Dietary Exclusion and food allergy:

Diagnosis of an IgE-mediated food allergy relies on a combination of medical history, skin prick test, serum IgE testing, and oral food challenges. History, skin prick test, and allergen-specific serum IgE are not diagnostic because of their limited positive predictive value for clinical allergy. The diagnostic criterion standard is a double-blind, placebo-controlled food challenge, which is often impractical in clinical practice, and is appropriately replaced by a single-blind or open food challenge. A challenge is preceded by the elimination of suspected foods for 2 to 8 weeks and is administered in a supervised medical setting to enable treatment of hypersensitivity reactions. If the challenge does not elicit symptoms, an allergy to that food allergy is not present. A food allergy is confirmed if the challenge elicits symptoms that correlate with medical history, blood testing, and skin prick results.

For patients with AD and a proven food allergy, elimination diets are appropriate and may decrease the severity of AD. Nutritionist consultation is indicated to avoid nutritional deficiencies and growth restriction. In addition, because food allergies often spontaneously resolve, patients should be reassessed regularly to avoid unnecessary elimination. For patients without a proven food allergy, elimination diets should not be pursued to manage AD, because there is no evidence to suggest that this approach is helpful. In addition, these diets may cause nutritional deficiencies, growth deficits, and anaphylaxis on re-exposure to previously tolerated foods.

Maternal diet and breastfeeding:

A detailed review found no significant protective effect of an antigen avoidance diet during pregnancy, lactation, or both for prevention the of AD in infants up to 18 months of age. In addition, maternal antigen avoidance during pregnancy was associated with a decreased mean gestational weight gain and birth weight and increased risk of preterm birth. 

In 2008, the American Academy of Pediatrics summarized the evidence for maternal and infant nutrition in the context of AD, that restriction of maternal diet during pregnancy and lactation does not affect subsequent AD development. Exclusive breastfeeding for 4 months in high-risk infants was reported to be protective against AD. A meta-analysis of 18 prospective studies and the German Infant Nutritional Intervention studies found decreased AD incidence in high-risk infants who were breastfed compared to those fed cow’s milk formula. This protective effect also applied to hydrolyzed formula. Conversely, no significant effect of exclusive breastfeeding on AD was observed for infants in the general population.

Conclusions

There is insufficient evidence to suggest a benefit from supplementation with vitamin D, Evening Primrose Oil, Borage Oil, fish oil, zinc sulphate, selenium, vitamin E, pyridoxine, sea buckthorn seed oil, hempseed oil, sunflower oil, and docosahexaenoic acid for AD. Evidence suggests that prebiotic supplementation in infants and prenatal followed by postnatal probiotic supplementation decrease the risk of atopic dermatitis. Elimination diets are only appropriate for patients who have a food allergy that is proven by oral food challenge. Maternal allergen avoidance diets during pregnancy or lactation do not prevent AD. Exclusive breastfeeding for 4 months or breastfeeding supplemented with hydrolyzed formula is protective against AD in high-risk infants. For infants at normal risk, breastfeeding does not affect the incidence of AD.