“Our study reveals that aside from eczema severity, this bacterium that patients with eczema commonly become colonized with could be an added risk factor for food sensitization and allergy,” Dr. Olympia Tsilochristou, lead author and clinical researcher at King’s College in London, told Allergic Living.
The researchers found that the children with severe eczema with S. aureus colonization (commonly called staph infection) produce more IgE antibodies – a marker of allergy – to peanut, egg and milk. This indicates sensitization to these foods.
The research team based their findings on data collected during the LEAP study, which followed children at high-risk for peanut allergy (due to having egg allergy or severe eczema or both) from infancy to 5 years of age; then for an additional year in a follow-up study. Groundbreaking results from that 2015 study showed that early introduction of peanut to babies reduced the risk of developing a peanut allergy by 70 to 80 percent.
Bacteria promoting allergy
But in this related study, the researchers found that even if fed peanut from a young age, babies with staph aureus bacteria on the skin and/or in the nose were more likely to develop peanut allergy.
“These findings indicate that Staphylococcus aureus may have reduced the chance of young infants gaining tolerance to peanut, even if peanut was eaten in early childhood,” said Dr. George du Toit, the King’s College professor who was co-author of LEAP and of this recent study.
If such children with severe eczema and staph aureus infection already had an egg allergy, which is often outgrown at a young age, that allergy was also likely to persist longer, according to the study published in the Journal of Allergy and Clinical Immunology.
During the LEAP study, at three age intervals, participants were assessed for eczema severity and IgE antibody levels, and skin and nasal passages were swabbed for the presence of S. aureus. These data were employed to arrive at the new study’s conclusions.
The association between staph infections in eczema and peanut allergy has been made previously. However, the new results add a significant understanding to the eczema, staph infection and food allergy relationship, as they are based on findings on a several year population study with highly controlled data. What’s still not clear is the mechanism to get from eczema plus bacteria to food allergy.
Where from here?
So does this mean we may soon see protection against S. aureus infection in eczema considered a food allergy prevention strategy, alongside the early introduction of peanut? “This is a very interesting concept and certainly a working hypothesis for future studies,” says Tsilochristou.
“Interventional studies eradicating S. aureus in early infancy, perhaps alongside early peanut introduction, will help elucidate its role in the development of food allergy,” she said.