Benefits of Dietary Elimination May Not Outweigh Risks in Atopic Dermatitis

Dietary elimination was associated with minimal improvement in eczema severity, pruritus, and sleeplessness among patients with mild to moderate atopic dermatitis (AD), although these benefits may prove insignificant due to potential risks. Results were published in The Journal of Allergy and Clinical Immunology: In Practice.

In assessing effective treatment options for AD, use of dietary elimination (excluding potential food allergies) has garnered conflcting views among clinicians and researchers.

AD has been associated with increased prevalence of food allergy, but the study authors say the relationship is complex and the directionality is unclear, whereas other factors unrelated to food have been implicated in the development and pathophysiology of AD, such as skin barrier dysfunction, immune dysregulation, and microbial dysbiosis from internal and external factors.

“Patients, caregivers, and clinicians may suspect food to trigger or worsen the presence or severity of eczema, whereas some clinicians are skeptical and reluctant to recommend dietary exclusions, in part because food avoidance diets may increase the risk for developing immunoglobulin E (IgE)-mediated allergy to excluded foods and nutritional deficiencies,” they noted.

With clinical evidence on the association remaining inconclusive, the researchers conducted a systematic review and meta-analysis to determine the benefits and risks of dietary elimination for the treatment of AD.

Randomized controlled trials (RCTs) and observational studies comparing dietary elimination and no dietary elimination for the treatment of AD from MEDLINE, Embase, AMED, PsycINFO, and the Cochrane Central Register of Controlled Trials databases from inception to January 18, 2022, were included in the analysis.

Primary outcomes assessed were eczema severity (measured via SCORing AD index [SCORAD], Patient-Oriented Eczema Measure, Eczema Area and Severity Index, area score, skin severity score, eczema activity score, and eczema severity score), pruritus severity (eg, total itch score, daytime itch score, pruritus score), and severity of sleep disturbance (eg, sleep disturbance score, sleeplessness score).

“We conducted random-effects meta-analyses of eczema outcomes. We used the grading of recommendations, assessment, development, and evaluation approach to assess certainty of evidence,” they explained.

Of the clinical studies assessed, 10 RCTs comprising 599 patients with AD (baseline median [IQR] of study mean age, 1.5 [0.5-4.8] years; median of study mean SCORAD, 20.7 [range, 3.5-37.6]) were included in the meta-analysis.

Compared with no dietary elimination, low-certainty evidence indicated that dietary elimination may slightly improve AD outcomes:

• Eczema severity based on the SCORAD improved 50% with dietary elimination vs 41% without dietary elimination by a minimally important difference (MID) of 8.7 points; risk difference for improving by MID was 9% (95% CI, 0%-17%)
• Pruritus severity based on daytime itch score (range, 0-3) improved with vs without dietary elimination by a mean difference of –0.21 [95% CI, –0.57 to 0.15)
• Severity of sleep disturbance based on sleeplessness score (range, 0-3) improved with vs without dietary elimination by a mean difference of –0.47 (95% CI, –0.80 to –0.13)

No credible subgroup differences based on elimination strategy (empiric vs guided by testing) or food-specific sensitization were observed. Although data addressing potential harms of elimination diets among included RCTs were insufficient, indirect evidence suggested that elimination diets may increase the risk for developing IgE-mediated food allergy.

The researchers concluded that the slight improvement observed in AD severity outcomes should be balanced against the potential risks for indiscriminate elimination diets for AD treatment, “especially in infants and young children at risk for developing IgE-mediated food allergy and nutritional deficiencies, and undertreating in the context of an increasing number of therapeutic options available to treat AD.”

Reference

Oykhman P, Dookie J, Al-Rammahy H, et al. Dietary elimination for the treatment of atopic dermatitis: a systematic review and meta-analysis. J Allergy Clin Immunol Pract. Published online July 19, 2022. doi:10.1016/j.jaip.2022.06.044