Is the bacteria S. aureus a risk factor for the development of food allergy in young children with eczema?
Published online: May 31, 2019
Staphylococcus aureus (SA) is a bacterium that can be found in the nose and the skin of healthy individuals; however, it is more common in sufferers of eczema. Aside from eczema, it has been implicated in the development and severity of allergic rhinitis, asthma, and food allergy. As S. aureus is a marker of more severe eczema which is a known risk factor for food sensitization/allergy, it may be that the association between S. aureus and food allergy in eczematous patients is statistically cofounded by eczema severity.
In an original article recently published in The Journal of Allergy & Clinical Immunology (JACI), Tsilochristou and colleagues investigated the association of S. aureus colonization (infection) with IgE (an antibody that mediates allergic reactions) production to common food allergens in early childhood independent of eczema severity. They also looked into the association between S. aureus and hen’s egg or peanut allergy independent of eczema severity. They used data collected during the LEAP and LEAP-On groundbreaking studies. The LEAP (Learning Early About Peanut Allergy) study had demonstrated that consumption of a peanut‐containing snack by infants who are at high‐risk for developing peanut allergy prevents later development of peanut allergy. The subsequent LEAP-On study showed that the protective effect of peanut consumption was maintained after a year of peanut avoidance.
The authors found that colonization of the skin with S. aureus at any time-point was associated with increased levels of hen’s egg and peanut IgE, independent of eczema severity. Additionally, participants with S. aureus were more likely to have their egg allergy persist at the age of 5 or 6 years which is the age by which most children with egg allergy are expected to have outgrown their egg allergy. Finally, they demonstrated that children with S. aureus had an increased risk for peanut allergy development at 5 or 6 years despite the fact that they were consuming peanut as part of the LEAP study protocol. The reported likelihood for persistent egg allergy and development of peanut allergy was independent of eczema severity.
These findings identify S. aureus as a risk factor for the development of food sensitization/allergy in young children with eczema, independent of eczema severity. In addition, S. aureus may prevent tolerance to foods. Therefore, there may be a role for S. aureus eradication in interventions aimed at inducing and maintaining tolerance to foods in young children with eczema.
The Journal of Allergy and Clinical Immunology (JACI) is the official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.