Eczema Patients Lack Natural Antibiotic

May Explain Why Skin Infections Are Common

From the WebMD Archives

Oct. 9, 2002 -- Researchers report they now know why people with eczema are prone to developing recurrent skin infections, and they say the findings could lead to better treatments for the chronic skin disease.

A new study suggests that people with eczema lack natural, protective antibiotics in their skin that are present in people with other inflammatory skin diseases, such as psoriasis. The study, published Oct. 10 in TheNew England Journal of Medicine, is the first to demonstrate a clinical significance for the naturally occurring antibiotics in humans.

Eczema, also known as atopic dermatitis, affects about 10% of infants and 3% of adults in the U.S., and is characterized by itchy, inflamed, easily irritated skin. Although the condition frequently improves during childhood or early adulthood, about half of patients are affected to some degree throughout life.

People with eczema are at increased risk for bacterial and viral skin infections, such as those caused by Staphylococcus aureus bacteria and herpes simplex virus. The latest findings suggest this may be due to the fact that eczema patients fail to produce effective amounts of two antibiotic proteins identified last year by Richard Gallo, MD, PhD, and colleagues at the University of California, San Diego.

"In most people, this immune response gets turned on when the skin is injured to protect against infection, but that does not appear to be the case in these patients," Gallo tells WebMD.

In this study, Donald Leung, MD, and colleagues at Denver's National Jewish Medical and Research Center analyzed skin samples from six healthy adults, eight with eczema, and 11 with psoriasis. Unlike eczema patients, those with psoriasis rarely have other skin infections.

Analysis showed that most psoriasis patients had at least 10 times as much of the two antibiotic proteins in their skin as patients with eczema, and that some eczema patients had no detectable levels of the natural antibiotics at all. Plus, levels of the antibiotic proteins found in the skin of psoriasis patients were able to kill colonies of the bacteria that cause staph infections.

"This study helps explain why 90% of [eczema] patients are colonized by Staphylococcus aureus and 30% develop active [staph] infections," Leung says.

Leung tells WebMD that a topical cream containing the antibiotic proteins may help protect eczema patients from developing skin infections.

"These [natural antibiotics] could be useful in fighting any type of bacterial infection," he says. "This would be especially important in fighting against infections caused by bacteria that are resistant to currently available synthetic antibiotics."

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