Skincare interventions in infants for preventing eczema and food allergy: A cochrane systematic review and individual participant data meta‐analysis

Abstract

Objective Eczema and food allergy start in infancy and have shared genetic risk factors that affect skin barrier. We aimed to evaluate whether skincare interventions can prevent eczema or food allergy. Design A prospectively planned individual participant data meta‐analysis was carried out within a Cochrane systematic review to determine whether skincare interventions in term infants prevent eczema or food allergy. Data sources Cochrane Skin Specialised Register, CENTRAL, MEDLINE, Embase and trial registries to July 2020. Eligibility criteria for selected studies Included studies were randomized controlled trials of infants <1 year with healthy skin comparing a skin intervention with a control, for prevention of eczema and food allergy outcomes between 1 and 3 years. Results Of the 33 identified trials, 17 trials (5823 participants) had relevant outcome data and 10 (5154 participants) contributed to IPD meta‐analysis. Three of seven trials contributing to primary eczema analysis were at low risk of bias, and the single trial contributing to primary food allergy analysis was at high risk of bias. Interventions were mainly emollients, applied for the first 3–12 months. Skincare interventions probably do not change risk of eczema by age 1–3 years (RR 1.03, 95% CI 0.81, 1.31; I2=41%; moderate certainty; 3075 participants, 7 trials). Sensitivity analysis found heterogeneity was explained by increased eczema in a trial of daily bathing as part of the intervention. It is unclear whether skincare interventions increase risk of food allergy by age 1–3 years (RR 2.53, 95% CI 0.99 to 6.47; very low certainty; 996 participants, 1 trial), but they probably increase risk of local skin infections (RR 1.34, 95% CI 1.02, 1.77; I2=0%; moderate certainty; 2728 participants, 6 trials). Conclusion Regular emollients during infancy probably do not prevent eczema and probably increase local skin infections.

Randomized controlled pilot trial with ion‐exchange water softeners to prevent eczema (SOFTER trial)

“…The magnitude of the point estimate of the relative risk (softened water/control) is 0.68 (95% CI 0.38, 1.2), which is consistent with the magnitude of risk reduction that might be expected by softening water based on the increased odds identified with hard water exposure in children in a recent systematic review and meta‐analysis conducted by our group (OR 1.28) 20 . However, there is uncertainty around the relative risk and, as observed in studies of emollient use for the prevention of eczema, encouraging findings from pilot data may not hold in a fully powered study 26,27 . Additionally, in the absence of longer‐term follow‐up, there is the possibility that use of a water softener in early life simply delays the onset of eczema rather than preventing it.…”

Potentially harmful substances in moisturizers

“…Furthermore, a recent systematic review with meta-analysis conducted by Cochrane showed that according to the available data, emollient therapy does not prevent eczema or FA. 2 Because detergents are very rarely present in moisturizers, we would like to draw attention to other detrimental ingredients frequently occurring in skin care products. 3 Haptens are low-molecular-weight chemicals that may cause irritant or allergic contact dermatitis or subclinical skin barrier function changes.…”

Epidermal Barrier Dysfunction in Atopic Dermatitis

“…In the last decades, several studies have tried to modify the IgE--sensitization-promoting microenvironment of AD skin to prevent the atopic march, but results have not been convincing. [154][155][156][157][158] Emollients and other general measures that enhance skin barrier repair from the very early days of life have generated contradictory results, eventually related to the diversity of emollients used. In fact, paraffin-based/alcohol-based/petroleum-based emollients can be detrimental in AD, since the occlusion inhibits keratinocyte differentiation and enhances S. aureus colonization, 159 whereas triple physiologic lipid-based barrier repair therapies composed of a ceramide-dominant mixture of the 3 key SC lipids (a 3:1:1 molar ratio of ceramides, cholesterol and free fatty acids) seem more effective.…”