In children with eczema, Staphylococcus aureus (S. aureus) colonization is associated with food allergies and sensitization, a finding that appears to be independent of eczema severity. This is according to a study published in the Journal of Allergy and Clinical Immunology.
The study was a secondary analysis of the Learning Early About Peanut Allergy (LEAP) and 12-month LEAP extension study (Persistence of Oral Tolerance to Peanut [LEAP-On]). Patients included in LEAP were infants aged <11 months to ≥4 years who presented with severe eczema, egg allergy, or both. The study randomly assigned patients to either avoid or consume peanut, and assessments were performed at baseline and at age 12 months, 30 months, and 60 months. Skin and nasal swabs were cultured for S aureus. Severity of eczema was assessed using the Scoring Atopic Dermatitis index, and specific immunoglobulin E levels were measured to identify sensitization.
Almost half of patients (48.8%) had some form of S aureus colonization, and colonization was associated with eczema severity across the LEAP cohort. Patients with skin/nasal S aureus colonization from baseline to 60 months were 1.57 times more likely to have a persistent egg allergy by 60 months of age compared with those who did not (95% CI, 1.02-2.42; P =.042). Compared with patients who were not colonized, those with skin and nasal S aureus colonization were 2.94 (95% CI, 1.11-7.76; P =.029) and 2.41 (95% CI, 1.04-5.59; P =.04), respectively, times as likely to have a peanut allergy at 60 months. At 60 and 72 months of age, individuals with skin S aureus colonization were 7.13 (95% CI, 1.14-44.47; P =.035) and 3.87 (95% CI, 1.02-14.65; P =.047) times as likely to have a peanut allergy, respectively, in the LEAP study compared with participants who were never skin S aureus colonized.
Limitations of the study were the inclusion of only children and infants, as well as the lack of genotype data for isolated strains.
“The role of S aureus as a potential environmental factor should be considered in future interventions aimed at inducing and maintaining tolerance to food allergens in eczematous infants,” the researchers concluded.
The authors disclosed no financial conflicts of interests with pharmaceutical companies, but reported several associations with organizations across the United States and Europe (full list available in study paper).
Tsilochristou O, du Toit G, Sayre PH, et al; for the Immune Tolerance Network Learning Early About Peanut Allergy Study Team. Association of Staphylococcus aureus colonization with food allergy occurs independently of eczema severity [published online May 29, 2019]. J Allergy Clin Immunol. doi:10.1016/j.jaci.2019.04.025