Early emollient therapy may reduce eczema, related food allergies, but data are mixed

LOUISVILLE, Ky. — Eczema and food allergy are linked, but children with severe, early-onset eczema before age 3 months are at highest risk, a speaker said at the American College of Allergy, Asthma & Immunology Annual Scientific Meeting.

Genetic and environmental factors also play a role, but there are mixed results on the value of preventive emollient therapy, Helen A. Brough, MA, MSc, PhD, consultant in pediatric allergy and head of service for Children’s Allergy Service at Evelina London Children’s Hospital, Guy’s and St. Thomas’ NHS Foundation Trust, said during her presentation.

“Environmental exposure to food allergens through inflamed, disrupted skin increases the risk for food sensitization and allergy,” Brough said. “Reducing the duration of eczema may increase the narrow window of opportunity to prevent food allergy through oral tolerance induction, and there is some evidence that early emollient may prevent eczema in children with parents who are atopic.”

Link between eczema, food allergy

It is well known that eczema is associated with food allergy development, Brough said.

For instance, data from the HealthNuts study, looking at a cohort of young infants from immunization clinics, showed that the age of onset and severity of eczema were strong indicators of food allergy.

Children aged younger than 3 months who were prescribed topical steroids for eczema had a 50% chance of developing challenge-proven peanut, egg or sesame seed allergy.

“This is a very high rate of food allergy, and this is something we obviously need to address,” Brough said.

Data in press from the LEAP study also show that this risk association between eczema and peanut allergy increases as children get older, Brough said. Specifically, among children aged 4 months to 6.7 months, those with mild eczema, based on a SCORAD score of less than 15, had a 2% risk for peanut allergy by age 11 months, with the risk increasing to 11% among those with a SCORAD of 15 to 40, and to 20% for those with a SCORAD of greater than 40, indicating severe eczema.

“But, in children who had had eczema for longer and who were older, they already had 20% or more risk of peanut allergy, even with just moderate eczema,” Brough said. “This shows the interplay between the age, duration and severity of eczema and food allergy.”

Data also are showing how environmental and genetic factors lead to epicutaneous damage, Brough said. This may include certain pathogens; viruses; bacteria, particularly Staphylococcus aureus; and fungi; as well as environmental exposures to detergents, food such as peanuts and high pH-containing creams that are often used in infants.

Mutations in the filaggrin (FLG) gene also are linked to increased risk for eczema and food allergy in children. Data have shown a gene-environment interaction, with environmental exposure to peanut dust leading to increased risk for peanut allergy among children with FLG null mutation (OR for each log exposure to peanut dust = 3.23; 95% CI, 1.07-9.79).

“This was done by taking dust from the infant’s bed and then quantifying this with an analyzer for peanut protein,” Brough said. “For example, if you have a peanut butter sandwich today, when you go home and sleep in your bed, your bed tomorrow will be full of peanut protein.”

Prevention, future research

Dry skin on its own is a risk factor for food sensitization and can be the first stage of eczema, leading to clinical inflammation and atopic dermatitis, Brough said. She added that it has been hypothesized, then, that food allergen exposure in the environment can permeate dry or inflamed skin, leading to food sensitization or allergy.

Thus, preventive emollient therapy may be helpful in preventing infants from progressing to inflamed skin and reducing their risk for food allergy.

For instance, transepidermal water loss, a measure of skin barrier dysfunction, among infants at 2 days and at 2 months predicts the onset of eczema at 1 year and food allergy at 2 years.

“So, this gives us a potential target before this condition has arisen,” Brough said.

In a Cochrane review of studies assessing preventive emollient therapy that included both high-risk infants and those from the general population, moisturizer use from early life showed no benefit in the prevention of eczema by age 1 to 3 years, with no evidence that it delayed the onset of eczema, either.

However, a subsequent systematic review and meta-analysis that separated out both high-risk infants, as well as those who had continuous moisturization vs. a gap in exposure, showed there was a reduction of eczema in both high-risk infants (RR = 0.84) and in atopic dermatitis among those who had continuous moisturization until eczema was assessed (RR = 0.59).

“Potentially, this means that this could delay the onset of eczema, and this is very important to give you more time to introduce food allergens for oral tolerance induction,” Brough said, adding a cautionary note that early use of moisturizer increased risk for skin infections with a trend toward increased risk for food allergy in the BEEP study.

There are multiple directions for future research to better assess this question, Brough said, including better assessing the optimal duration of preventive emollient therapy and improving parental adherence, the role of environmental foods and Staphylococcus, the difference between primary and secondary prevention, and the role of Th2.

There are some data suggesting that different types of emollients will have different outcomes, particularly for the use of ceramides in preventing transepidermal water loss, with one study showing use of a ceramide-based balm between 0 to 8 weeks led to an almost 50% reduction in the point prevalence of eczema at 1 year and no increased risk for skin infections.

“Between 0 and 8 weeks is when changes in the skin are most rapid, in terms of transepidermal water loss, because the baby is going from being in an intrauterine aqueous condition to being in air,” Brough said.

Brough also mentioned she is a researcher of the ongoing NIH-funded SEAL, or Stopping Eczema and Allergy, study, which will assess the use of two different types of emollients and proactive skin care and the effect on reducing food and respiratory allergies.

References:

• Brough HA, et al. J Allergy Clin Immunol. 2015;doi:10.1016/j.jaci.2014.10.007.
• Kelleher MM, et al. Cochrane Database Syst Rev. 2021;doi:10.1002/14651858.CD013534.pub2.
• Kelleher MM, et al. J Allergy Clin Immunol. 2016;doi:10.1016/j.jaci.2015.12.1312.
• Martin PE, at al. Clin Exp Allergy. 2015;doi:10.1111/cea.12406.
• Ní Chaoimh C, et al. Allergy. 2022;doi.10.1111/all.15491.