Dust Mites May Affect Eczema

Dust mites, which infest even the cleanest homes and thrive in bedding and carpets, disrupt the protective function of the skin, leaving it vulnerable to other allergens and irritants in the environment, a study has found.
House dust mites and their droppings have long been linked to attacks of asthma and eczema, and a group of researchers in Japan has offered an explanation as to how that happens.
In a paper to be published in the Journal of Investigative Dermatology, the researchers found that mites and their faeces contain an enzyme, which destroys the protective function of the skin, leaving it vulnerable to other irritants.
"People go to hospital only after they develop severe (skin) disease, but little is known as to what happened or what caused it," Toshiro Takai of the Atopy (Allergy) Research Center at the Juntendo University School of Medicine in Tokyo told Reuters.
"Our study suggests that it may be due to the disruption of the barrier function of the skin (by the dust mite)."
In their experiment, the scientists dabbed hairless mice with solution containing the mite enzyme and observed that the rodents soon suffered water loss on their skins.
They then dabbed the mice with riboflavin - or vitamin B2 - which is accepted in the scientific community as a substitute for allergens and irritants in the environment.
"We observed in the mice transepidermal water loss, which is an indication of disruption of the skin barrier. We also observed the penetration of riboflavin into the skin," Takai said.
Takai said the finding provides an explanation for skin-related allergies in humans and he hopes dermatologists would investigate more closely into the role of the dust mite.
"In a healthy person, the barrier is complete and irritants can't get into the skin. But partial disruption of the barrier facilitates passage of allergens and other irritants," he said.
According to the World Health Organisation, asthma affected 300 million people worldwide in 2005, killing 255,000 of them. The death figure is expected to increase by 20 percent in 10 years' time if urgent action if not taken.

Reuters Health