S. aureus puts kids with severe eczema at higher risk for food allergy

A defective skin barrier, aberrant local skin immunity and microbial dysfunction all contribute to the pathogenesis of eczema. Recent evidence has also shown that staph aureus overgrowth, in addition to eczema, places a child at even greater risk of food allergies as demonstrated in an extension of the LEAP study, described below.

Numerous studies have implicated Staphylococcus aureus in the development of eczema.

Now, in a secondary analysis of the Learning About Peanut Allergy, or LEAP, study, researchers have found that children with severe eczema who were colonized with the bacteria were significantly more likely to have a specific food allergy.

In LEAP, 640 children aged 4 to 11 months with severe eczema, egg allergy, or both were randomly assigned to consume or avoid peanuts until 60 months of age. The study found that the early introduction of peanuts significantly reduced the frequency of the development of peanut allergy. During the study, researchers documented children’s eczema severity and tested for S. aureus colonization at four different time points.

“This design provides a unique opportunity for the detailed investigation of the relationship between S. aureus and food allergy,” the researchers wrote.

In a secondary analysis of LEAP and a 12-month extension of that study, called LEAP-On, researchers investigated the association between S. aureus colonization and specific immunoglobulin E production to common food allergens in early childhood — such as milk, eggs or peanuts — independent of eczema severity. They also sought to determine the association of S. aureus colonization with eczema severity and persistence.

They found that although S. aureus colonization was associated with eczema throughout the study period, children who were colonized at ages 12 and 60 months demonstrated eczema deterioration.

Colonization with the bacteria at any time during the study was linked to increased hen’s egg white and peanut specific IgE levels. Furthermore, children colonized with S. aureus experienced persistent egg and peanut allergy at ages 60 and 72 months. These associations persisted regardless of eczema severity.

“This is significant because most children with egg allergy usually outgrow this at an earlier age,” study author Olympia Tsilochristou, MD, a clinical research fellow at King’s College London, said in a press release.

The researchers wrote that the relationship between eczema, S. aureus colonization and food allergy could be important in providing food allergy interventions.

“We do not know yet the exact mechanisms that lead from eczema to food allergy,” Tsilochristou said. “However, our results suggest that the bacteria S. aureus could be an important factor contributing to this outcome.” – by Katherine Bortz

Disclosures: Tsilochristou reports receiving grants from the Clemens von Pirquet Foundation in Geneva, Switzerland, during the conduct of the study. Please see the study for all other authors’ relevant financial disclosures.

Reference:

Du Toit G, et al. N Eng J Med. 2015;doi:10.1056/NEJMoa1414850.

Tsilochristou O, et al. J Allergy Clin Immunol. 2019;doi:10.1016/j.jaci.2019.04.025.

Also see https://www.allergyfoundation.co.za/eczema-linked-to-food-allergy/

https://www.allergyfoundation.co.za/is-chronic-eczema-caused-by-food-allergies/