Abstract: Objectives To determine the prevalence of Staphylococcus aureus (S. Aureus) colonization and S. aureus-derived exotoxins in lesions of childhood atopic dermatitis (AD) and evaluate the role of S.aureus-derived exotoxins in the pathogenesis of childhood AD. Methods Specimens were taken from the skin lesions of 148 patients, non-lesional skin of 30 patients, and the skin of 250 controls for bacterial cultures. S. aureus-derived exotoxins were detected by reverse passive latex agglutination. Total IgE levels were determined with immunoradiometric assay. Results The prevalence of S. aureus colonization was significantly increased in both the lesional and non-lesional skin of patients with AD in comparison with the controls (P<0.01). There was a positive correlation between the AD severity, as measured by SCORAD index, and S. aureus colonization (P<0.01). There was no significant difference in the exotoxin-producing S. aureus isolated between the patients and controls. Moreover, the disease severity was not markedly different between patients with and without exotoxin-producing S. aureus (P>0.05). However, patients with increased total IgE levels showed significantly high SCORAD indices (P<0.01). Conclusions The results indicate that S. aureus could be isolated from 43.24% of AD lesions, in which 47.45% of the isolates could secret exotoxins, especially staphylococcal enterotoxin B.

Key words: Dermatitis, atopic, Staphylococcus aureus, Exotoxins, Superantigens