Skin care interventions in infants for preventing eczema and food allergy New

Abstract

Background

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.

Objectives

Primary objective 

To assess effects of skin care interventions, such as emollients, for primary prevention of eczema and food allergy in infants

Secondary objective 

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.

Search methods

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 We contacted field experts to identify planned trials and to seek information about unpublished or incomplete trials.

Selection criteria

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.

Data collection and analysis

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.

Main results

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.

Authors' conclusions

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.

Author(s)

Maeve M Kelleher, Suzie Cro, Victoria Cornelius, Karin C Lodrup Carlsen, Håvard O Skjerven, Eva M Rehbinder, Adrian J Lowe, Eishika Dissanayake, Naoki Shimojo, Kaori Yonezawa, Yukihiro Ohya, Kiwako Yamamoto-Hanada, Kumiko Morita, Emma Axon, Christian Surber, Michael Cork, Alison Cooke, Lien Tran, Eleanor Van Vogt, Jochen Schmitt, Stephan Weidinger, Danielle McClanahan, Eric Simpson, Lelia Duley, Lisa M Askie, Joanne R Chalmers, Hywel C Williams, Robert J Boyle

Abstract

Plain language summary

Skin care interventions for preventing eczema and food allergy 

Does moisturising baby skin prevent eczema or food allergies? 

Key messages 

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.

Author(s)

Maeve M Kelleher, Suzie Cro, Victoria Cornelius, Karin C Lodrup Carlsen, Håvard O Skjerven, Eva M Rehbinder, Adrian J Lowe, Eishika Dissanayake, Naoki Shimojo, Kaori Yonezawa, Yukihiro Ohya, Kiwako Yamamoto-Hanada, Kumiko Morita, Emma Axon, Christian Surber, Michael Cork, Alison Cooke, Lien Tran, Eleanor Van Vogt, Jochen Schmitt, Stephan Weidinger, Danielle McClanahan, Eric Simpson, Lelia Duley, Lisa M Askie, Joanne R Chalmers, Hywel C Williams, Robert J Boyle

Reviewer's Conclusions

Authors' conclusions 

Implications for practice 

This review found that skin care interventions such as emollients probably do not influence the development or time to onset of eczema in healthy term infants by age one to two years and probably increase the risk of skin infection (moderate‐certainty evidence). This suggests that regular application of emollients or other skin care interventions probably is not necessary for healthy infants, unless there are other specific reasons for using such products. This information should be taken into account by guideline developers in this field. Given the probable increase in local skin infection risk, it may be important for carers to practise appropriate hygiene measures when applying emollients to the skin of infants.

This review could not draw conclusions about the impact of skin care interventions on IgE‐mediated food allergy by age one to two years (very low‐certainty evidence); only one study had food allergy diagnosed by oral food challenges, and in this study, only 29% of eligible participants attended for oral food challenge (OFC). Low‐certainty evidence from one trial suggests that skin care intervention may slightly increase parent reports of immediate food allergy (to a common allergen) at two years. However, this outcome was only detected in cow’s milk, which may be unreliable as a measure due to the commercially influenced over‐reporting of cow's milk allergy in infants. Evidence was insufficient to detect effects of skin care interventions on food sensitisation at age one to two years (very low‐certainty evidence). The gold standard for diagnosing food allergy is an OFC; however, these are costly and time consuming for participants and trialists. Alternative modes of diagnosis of food allergy, by standardised questionnaires and documented sensitisation, or even by more complex methods such as basophil activation test, could be considered in further trials.

Infant slippages and stinging/allergic reactions to moisturisers may increase with the use of skin care interventions during infancy (low‐certainty evidence), although confidence intervals for slippages and stinging/allergic reactions are wide and include the possibility of no effect or reduced risk. All results presented here are in comparison to standard care.

Subgroup analysis showed that age, hereditary risk, FLG mutation, duration of intervention, and classification of intervention type did not have an impact on the risk of developing eczema. We could not evaluate these effects for food allergy risk. We do not know if adherence to treatment effects the relationship between skin care interventions and risk of developing eczema or food allergy.

The common clinical practice of applying emollients to the skin of people who already have eczema is not directly affected by our findings.

Implications for research 

In this review, the trials with eczema as an outcome were mainly emollient trials. Other methods of skin barrier intervention in this review had very short follow‐up and did not measure eczema as an outcome, so their impact on eczema remains unclear. Potential future studies on bathing practices should have longer follow‐up of clinical outcomes that use standard methods of eczema measurement. Trialists may wish to consider using novel interventions that impact skin barrier function, rather than those that have already been evaluated in these trials.

We were unable to identify whether skin care interventions such as emollients have an impact on risk of developing food allergy. More research is needed to identify whether food allergy risk is influenced by early skin care practices. Future trials should measure food allergy using a robust outcome assessment (Asai 2020), and researchers may wish to consider applying published algorithms to evaluate food allergy outcomes in participants who do not undergo oral food challenge (Kelleher 2020b). The paucity of oral food challenge‐diagnosed food allergy outcomes in this meta‐analysis infers that oral food challenges are difficult to conduct and are infrequently attended in prevention studies. We would suggest that future studies incorporate Core Outcome Measures for Food Allergy. An update of this review with food allergy outcomes from Skjerven 2020 and potentially the other ongoing trials with foods allergy outcomes will be needed to fully address the hypothesis that skin care interventions may impact the risk of food allergy (Lowe 2019; NCT03871998; NCT03808532).

Conclusions on adherence to intervention could not be made, and we would suggest that future studies carefully document adherence and compliance with interventions. Also, collaboration between groups regarding future potential studies may allow for larger numbers with less imprecision.

This review focused on primary prevention of eczema and food allergy, preventing the diagnosis of eczema and food allergy in infants. Given the strong links between early‐onset eczema and food allergy, another body of work has begun on secondary prevention of food allergy among infants already diagnosed with eczema. These trials ‐ NCT03742414 and UMIN000028043 ‐ include infants younger than 13 weeks with diagnosed eczema and randomise them to active eczema management from onset with emollient and topical corticosteroids. Both studies have IgE‐mediated food allergy as a primary outcome and are ongoing.

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