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Study Shows Factors Making Eczema Sufferers More Susceptible to Infections

Posted: July 9, 2009

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Vaccinia virus, which is used in smallpox vaccinations, can also cause a serious and life-threatening skin infections in a smaller subset of patients. People who have eczema or had it in the past are susceptible to this infection when they receive a smallpox vaccination. This situation could limit the ability of those people to safely receive vaccinations in case of a smallpox bioterrorism event.

The Atopic Dermatitis Vaccinia Network (ADVN) is an NIH-funded multicenter network charged with better understanding the susceptibility of eczema patients to the vaccinia infection and to search for ways to protect against it. Atopic dermatitis is another name for eczema, an allergic skin condition that causes itchy, inflamed and cracked skin.

The ADVN researchers believed they might be able to identify eczema patients at high risk for these infections and to obtain clues about the mechanisms of susceptibility by studying a large cohort of patients who had suffered eczema herpeticum, the herpes simplex viral skin infections. They examined a wide variety of demographic, pathologic and biologic characteristics  in 901 subjects, 138 of whom had suffered eczema herpeticum.

They found that eczema patients susceptible to herpes simplex infections had more severe disease, earlier age of disease onset, more frequent history of other allergic diseases such as food allergy, asthma and hay fever, more allergic biomarkers, and more frequent skin infections with other microbes. "These characteristics associated with eczema herpeticum should help us identify young patients at greater risk for eczema herpeticum so that we can be more vigilant with them and better equipped to prevent this serious complication of eczema," said Dr. Leung.

The greater allergic disease and sensitization, as well as infection by other microbes, point to a potential mechanism for the increased susceptibility to viral skin infections. An emerging model of eczema highlights the importance of skin-barrier defects and a lack of antimicrobial proteins among eczema patients. The skin-barrier defect is believed to result in the greater allergic sensitization among eczema patients in general. The even higher allergic sensitization among EH patients suggests the skin-barrier defect is particularly acute in those patients. The higher levels of infections with staphylococcus and other microbes suggests that EH patients may be particularly lacking in antimicrobial proteins.