May 24 (iVillage Total Health) -- If you're looking for an excuse to slack off on dusting, a new study may help you feel a little less guilty about having a dusty house.

Researchers from Arizona studied 484 children ages 5 and under and tested their homes for the presence of endotoxin -- a toxic substance that is part of bacteria cells responsible for many diseases. When bacteria cells die off or are damaged, endotoxins are released. The study found that children with higher levels of endotoxins in their homes were less likely to have eczema or develop wheezing or breathing problems by the time they reached 3 years of age.

Eczema is an itchy, noncontagious inflammation of the skin that usually begins in childhood. In most cases, eczema begins as intense itching, followed by a patchy skin rash that is red, inflamed, dry and scaly. The rash most often affects the face, arms and legs as well as the creases of the hands and feet.

The exact cause of eczema is unknown. However, scientists believe that the disease has a genetic component, because it tends to run in families. Flare-ups often occur when a child is exposed to certain allergens or irritants. However, many other factors can trigger symptoms, including stress and environmental factors such as exposure to temperature extremes and infections.

According to the National Eczema Association for Science and Education, nearly 10 percent of all infants and children have eczema at some point. It typically begins within the first year of a child's life, but many children begin to see improvement by 5 or 6 and more than half grow out of the problem by their teen years.

"We're trying to find why children exposed to endotoxin have lower levels of disease early in life," Melisa Celaya, a researcher from the Arizona Respiratory Center, said in a press release. She said increased levels of endotoxin in the homes of the children studied may have been due to the age and condition of the homes, use of carpeting and the presence of mold and interior wall leaks.

"We'll be looking at the relationship between endotoxin levels in the home and chemicals (called cytokines) that are produced by certain immune system cells, to see why children exposed to lower levels are developing more allergic symptoms later on," she added. "This study is unusual in that we are following children over a long period, and are looking at both environmental factors and immunological factors, so we can correlate the two."

Results of the study were presented May 20 at the American Thoracic Society 2007 International Conference.

Copyright 2007 iVillage Total Health.