Comparison of the severity of atopic dermatitis lesions and the density of Staphylococcus aureus on the lesions after antistaphylococcal treatment.

We examined the relationship between atopic dermatitis (AD) and Staphylococcus aureus by comparing changes in AD lesions and the bacterial density on the lesions after antimicrobial treatment with cefdinir. We found that there was a greater density of S. aureus on red erythemas and exudative lesions than in light/dark red erythemas and non-exudative lesions of AD. Forty-one of 59 cases (69%) showed a decrease in colony count following antimicrobial treatment. In 28 of 39 cases (72%) there was a decrease of erythema, and in 18 of 22 cases (82%) there was a decrease in the amount of exudate both associated with a decrease in colony density following antimicrobial treatment. Because acute phases of atopic dermatitis, such as red erythemas and exudative lesions, were closely related to the colonization of S. aureus, dense colonization with S. aureus may be an important factor in the exacerbation of AD. We believe that staphylococcal products such as α-toxin, various enzymes, coagulase, and superantigenic exotoxins affect some aspect of the inflammatory process, resulting in exacerbation of AD. J Infect Chemother 1996;2:70-74.