Does moisturising baby skin prevent eczema or food allergies?
Skin care treatments in babies, such as using moisturisers on the skin during the first year of life, probably do not stop them from developing eczema, and probably increase the chance of skin infection.
We are uncertain how skin care treatments might affect the chances of developing a food allergy. We need evidence from well-conducted studies to determine effects of skin care on food allergies in babies.
What are allergies?
An immune response is how the body recognises and defends itself against substances that appear harmful. An allergy is a reaction of the body's immune system to a particular food or substance (an allergen) that is usually harmless. Different allergies affect different parts of the body, and their effects can be mild or serious.
Food allergies and eczema
Eczema is a common skin allergy that causes dry, itchy, cracked skin. Eczema is common in children, often developing before their first birthday. It is sometimes a long-lasting condition, but it may improve or clear as a child gets older.
Allergies to food can cause itching in the mouth, a raised itchy red rash, swelling of the face, stomach symptoms or difficulty breathing. They usually happen within 2 hours after a food is eaten.
People with food allergies often have other allergic conditions, such as asthma, hay fever, and eczema.
Why we did this Cochrane Review
We wanted to learn how skin care affects the risk of a baby developing eczema or food allergies. Skin care treatments included:
• putting moisturisers on a baby's skin;
• bathing babies with water containing moisturisers or moisturising oils;
• advising parents to use less soap, or to bathe their child less often; and
• using water softeners.
We also wanted to know if these skin care treatments cause any unwanted effects.
What did we do?
We searched for studies of different types of skin care for healthy babies (aged up to one year) with no previous food allergy, eczema, or other skin condition.
Search date: we included evidence published up to July 2020.
We were interested in studies that reported:
• how many children developed eczema, or food allergy, by age one to three years;
• how severe the eczema was (assessed by a researcher and by parents);
• how long it took for eczema to develop;
• parents' reports of immediate (under two hours) reactions to a food allergen;
• how many children developed sensitivity to a particular food allergen; and
• any unwanted effects.
We assessed the strengths and weaknesses of each study to determine how reliable the results might be. We then combined the results of all relevant studies and looked at overall effects.
What we found
We found 33 studies involving 25,827 babies. These studies took place in Europe, Australia, Japan, and the USA, most often at children's hospitals. Skin care was compared against no skin care or care as usual (standard care). Treatment and follow-up times ranged from 24 hours to two years. Many studies (13) tested the use of moisturisers; others mainly tested the use of bathing and cleansing products and how often they were used.
We combined the results of 11 studies; eight included babies thought to have high risk of developing eczema or a food allergy.
What are the main results of our review?
Compared to no skin care or standard care, moisturisers:
• probably do not change the risk of developing eczema by the age of one to two years (evidence from 7 studies in 3075 babies) nor the time needed for eczema to develop (9 studies; 3349 babies);
• may slightly increase the number of immediate reactions to a common food allergen at two years, as reported by parents (1 study; 1171 babies);
• probably cause more skin infections (6 studies; 2728 babies);
• may increase unwanted effects, such as a stinging feeling or an allergic reaction to moisturisers (4 studies; 343 babies); and
• may increase the chance of babies slipping (4 studies; 2538 babies).
We are uncertain whether skin care treatments affect the chance of developing a food allergy as assessed by a researcher (1 study; 996 babies) or sensitivity to food allergens (2 studies; 1055 babies) at age one to two years.
Confidence in our results
We are moderately confident in our results for developing eczema and the time needed to develop eczema. These results might change if more evidence becomes available. We are less confident about our results for food allergy or sensitivity, which are based on small numbers of studies with widely varied results. These results are likely to change when more evidence is available. Our confidence in our findings for skin infections is moderate but is low for stinging or allergic reactions and slipping.
Skin care interventions such as emollients during the first year of life in healthy infants are probably not effective for preventing eczema, and probably increase risk of skin infection. Effects of skin care interventions on risk of food allergy are uncertain.
Further work is needed to understand whether different approaches to infant skin care might promote or prevent eczema and to evaluate effects on food allergy based on robust outcome assessments.
Eczema and food allergy are common health conditions that usually begin in early childhood and often occur together in the same people. They can be associated with an impaired skin barrier in early infancy. It is unclear whether trying to prevent or reverse an impaired skin barrier soon after birth is effective in preventing eczema or food allergy.
To assess effects of skin care interventions, such as emollients, for primary prevention of eczema and food allergy in infants
To identify features of study populations such as age, hereditary risk, and adherence to interventions that are associated with
the greatest treatment benefit or harm for both eczema and food allergy.
We searched the following databases up to July 2020: Cochrane Skin Specialised Register, CENTRAL, MEDLINE, and Embase. We searched two trials registers and checked reference lists of included studies and relevant systematic reviews for further references to relevant randomised controlled trials (RCTs). We contacted field experts to identify planned trials and to seek information about unpublished or incomplete trials.
RCTs of skin care interventions that could potentially enhance skin barrier function, reduce dryness, or reduce subclinical inflammation in healthy term (> 37 weeks) infants (0 to 12 months) without pre-existing diagnosis of eczema, food allergy, or other skin condition were included. Comparison was standard care in the locality or no treatment. Types of skin care interventions included moisturisers/emollients; bathing products; advice regarding reducing soap exposure and bathing frequency; and use of water softeners. No minimum follow-up was required.
This is a prospective individual participant data (IPD) meta-analysis. We used standard Cochrane methodological procedures, and primary analyses used the IPD dataset. Primary outcomes were cumulative incidence of eczema and cumulative incidence of immunoglobulin (Ig)E-mediated food allergy by one to three years, both measured by the closest available time point to two years. Secondary outcomes included adverse events during the intervention period; eczema severity (clinician-assessed); parent report of eczema severity; time to onset of eczema; parent report of immediate food allergy; and allergic sensitisation to food or inhalant allergen.
This review identified 33 RCTs, comprising 25,827 participants. A total of 17 studies, randomising 5823 participants, reported information on one or more outcomes specified in this review. Eleven studies randomising 5217 participants, with 10 of these studies providing IPD, were included in one or more meta-analysis (range 2 to 9 studies per individual meta-analysis).
Most studies were conducted at children's hospitals. All interventions were compared against no skin care intervention or local standard care. Of the 17 studies that reported our outcomes, 13 assessed emollients. Twenty-five studies, including all those contributing data to meta-analyses, randomised newborns up to age three weeks to receive a skin care intervention or standard infant skin care. Eight of the 11 studies contributing to meta-analyses recruited infants at high risk of developing eczema or food allergy, although definition of high risk varied between studies. Durations of intervention and follow-up ranged from 24 hours to two years.
We assessed most of this review's evidence as low certainty or had some concerns of risk of bias. A rating of some concerns was most often due to lack of blinding of outcome assessors or significant missing data, which could have impacted outcome measurement but was judged unlikely to have done so. Evidence for the primary food allergy outcome was rated as high risk of bias due to inclusion of only one trial where findings varied when different assumptions were made about missing data.
Skin care interventions during infancy probably do not change risk of eczema by one to two years of age (risk ratio (RR) 1.03, 95% confidence interval (CI) 0.81 to 1.31; moderate-certainty evidence; 3075 participants, 7 trials) nor time to onset of eczema (hazard ratio 0.86, 95% CI 0.65 to 1.14; moderate-certainty evidence; 3349 participants, 9 trials). It is unclear whether skin care interventions during infancy change risk of IgE-mediated food allergy by one to two years of age (RR 2.53, 95% CI 0.99 to 6.47; 996 participants, 1 trial) or allergic sensitisation to a food allergen at age one to two years (RR 0.86, 95% CI 0.28 to 2.69; 1055 participants, 2 trials) due to very low-certainty evidence for these outcomes. Skin care interventions during infancy may slightly increase risk of parent report of immediate reaction to a common food allergen at two years (RR 1.27, 95% CI 1.00 to 1.61; low-certainty evidence; 1171 participants, 1 trial). However, this was only seen for cow’s milk, and may be unreliable due to significant over-reporting of cow’s milk allergy in infants. Skin care interventions during infancy probably increase risk of skin infection over the intervention period (RR 1.34, 95% CI 1.02 to 1.77; moderate-certainty evidence; 2728 participants, 6 trials) and may increase risk of infant slippage over the intervention period (RR 1.42, 95% CI 0.67 to 2.99; low-certainty evidence; 2538 participants, 4 trials) or stinging/allergic reactions to moisturisers (RR 2.24, 95% 0.67 to 7.43; low-certainty evidence; 343 participants, 4 trials), although confidence intervals for slippages and stinging/allergic reactions are wide and include the possibility of no effect or reduced risk.
Preplanned subgroup analyses show that effects of interventions were not influenced by age, duration of intervention, hereditary risk, FLG mutation, or classification of intervention type for risk of developing eczema. We could not evaluate these effects on risk of food allergy. Evidence was insufficient to show whether adherence to interventions influenced the relationship between skin care interventions and risk of developing eczema or food allergy.