Children with a history of AD have increased prevalence of impetigo
MedWire News: Young children with a history of atopic dermatitis (AD) have an increased lifetime prevalence of impetigo contagiosum (IC) compared with those without AD, report Japanese researchers.
To assess whether children with AD have increased lifetime prevalence of IC, molluscum contagiosum (MC), and herpes virus infection (HI), Sayaka Hayashida (Kyushu University, Fukuoka) and colleagues recruited 913 children aged 0-6 years from nursery schools in Ishigaki City in the Okinawa Prefecture.
The children were examined by dermatologists and information on allergic disease and previous skin infections or AD was collected through questionnaires filled out by the children's parents or guardians.
Overall, 132 children had current or previous AD. In the total cohort, 45.1%, 19.7%, and 2.5% of the children had a history of IC, MC, or HI, respectively.
The team found that only a history of IC was linked to positive AD status. Children with AD were 1.8 times more likely to have had IC during their lifetime than children without AD.
Boys were more likely to have had MC than girls, but there was no significant link with AD. Previous HI was not significantly associated with any of the factors assessed in this study.
"In IC, bacteria do not infect intact skin, but instead enter through sites of minor trauma," write Hayashida and team in the Journal of Dermatological Science.
"Most AD patients are colonized with Staphylococcus aureus, which may be cultured from skin lesions and, to a lesser degree, from nonlesional skin. Mechanical trauma caused by scratching due to itching is believed to result in barrier dysfunction leading to skin surface infection in AD."
They conclude: "We consider this to be the first demonstration that the lifetime prevalence of IC, but not that of MC or HI, did indeed increase in AD children compared with their non-AD counterparts.
"Our findings may support the presence of defective cutaneous innate immunity in AD."
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By Helen Albert