Atopic Dermatitis: Nutritional Considerations

Nutritional modifications that may improve atopic dermatitis have been under study for many years. The following factors are under investigation:

Avoiding Alcohol during Pregnancy

In cases in which both parents had allergic diseases, maternal alcohol intake equivalent to four or more drinks per week increased the risk for atopic dermatitis fourfold.⁹ Alcohol use during pregnancy carries other major risks and should be avoided completely.

Breast-feeding

Breast-feeding allows infants to avoid exposure to cow's milk proteins, except insofar as they may be transmitted from the maternal diet through breast milk, as has been demonstrated in studies of colicky infants (see Colic chapter). Avoidance of allergenic foods by a breast-feeding mother may further reduce risk of atopy in the infant. Some have suggested that breast milk supplies specific protective factors as well, notably transforming growth factor β2, a cytokine that provides anti-allergenic immunoprotection. Diminished production of this cytokine has been reported in persons with atopic eczema and in the breast milk from mothers with atopy.¹⁰

Extensively Hydrolysed Whey Protein Formulas

Hydrolyzed formulas have been used in children who are not breast-fed to reduce the incidence of atopic dermatitis, and are tolerated by at least 90% of infants with documented allergy to cow's milk protein.¹¹ However, these formulas retain some allergenicity, and only amino acid-based formulas can be considered completely nonallergenic.¹²

Delayed Introduction of Solid Foods

Avoiding the introduction of solid foods until infants have reached 4 to 6 months of age appears to reduce the risk of atopy. A combination of breast-feeding (or hypoallergenic formula) and delayed introduction of solid food appears to be the most effective regimen for atopy prevention in infants.¹³ This approach may be augmented by environmental controls, such as polyvinyl mattress covers and anti-dust-mite sprays. In a clinical trial, these combined steps were associated with a 67% reduction in dermatitis incidence, compared with a control population.¹⁴

Eliminating Allergy-Causing Foods

Eggs, cow's milk, soy, and wheat account for roughly 90% of the allergenic foods in children with atopic dermatitis.¹⁵ More than 50% of children with diet-related atopic dermatitis experience both a significant improvement during periods of dietary exclusion and an exacerbation of their condition when challenged with allergen-containing foods.¹⁵

Adults with eczema are more likely than children with the condition to experience exacerbations when exposed to foods containing birch pollen, such as apple, carrots, celery, and hazelnuts.¹⁵ (See Rheumatoid Arthritis for instructions on elimination diets.)

Double-blind, placebo-controlled food challenges have found that a small fraction of children and adults experience skin reactions when given various additives. These include nitrite, benzoate, and tartrazine, balsam of Peru, and both natural and artificial vanilla.^16,17 More than 50% of patients have been reported to improve on diets low in allergens.¹⁶

Vegetarian Diets

Preliminary evidence indicates that a vegetarian diet results in significant improvement in SCORAD (SCORing Atopic Dermatitis), a clinical tool for objectively assessing the severity of atopic dermatitis. This improvement appears to be related to reductions in circulating blood levels of eosinophils and neutrophils and decreased monocyte production of PGE2, an inducer of IgE and T helper 2 (Th2) cell production.¹⁸ A low-energy diet (55% of estimated energy needs) conferred similar benefit to individuals with atopic dermatitis,¹⁹ although the practicality of energy-restricted regimens for long-term use is not established.

Probiotic Therapy

Prenatal treatment with Lactobacillus in mothers with a family history of atopic disease, combined with postnatal probiotic treatment of their infants, reduced the incidence of infant atopic dermatitis by 50%.20 Probiotic therapy also significantly reduced SCORAD in infants21 and in children.²² An excess of Th2 cells may be involved in IgE synthesis and the development of dermatitis, and diet appears to have a role in this process.^18,23 Probiotic treatment (mainly Lactobacillus rhamnosus) may have anti-allergy effects by stimulating Th1 cytokines²¹ and by down-regulating CD34+ cells involved in the symptoms of dermatitis, while increasing those with anti-inflammatory effects (eg, interferon-γ).²⁰

Vitamin E

Preliminary data indicate that supplementary vitamin E (400 IU/day) improves symptoms in some adults with this disease.²⁴ Lack of antioxidants may encourage Th2 cell production characteristic of atopy.²⁵ Vitamin E tends to increase Th1 cell production and reduces IgE-mediated responses, which may explain why studies have found inverse associations between vitamin E intake and the risk for atopic eczema.^25,26

Orders

See Basic Diet Orders.

Elimination diet, if specific triggers for dermatitis have not been found.

What to Tell the Family

Atopic dermatitis is a persistent ailment with a significant hereditary component. Some evidence indicates that the risk for inheriting this disease can be moderated through breast-feeding and allergen avoidance. In persons with established disease, effective management of symptoms is possible through combinations of topical ointments, diet modification, dietary supplements, and, if necessary, systemic anti-inflammatory (corticosteroid) treatment.