Cats Can Hamper Breathing Even in Non-Allergic

(Page 2)

Shier also suggested that schools and other public places where cat and other allergens are likely to be present should give more attention to cleaning hard surfaces and avoiding carpeting.

He noted that cat allergens are particularly widespread because they are "stickier," smaller and lighter than other allergens, which makes them easily airborne. As a result, a person could be exposed without being in the presence of cats. That's why Chinn's group found cat allergen to be ubiquitous in the mattress dust of both cat owners and non-owners.

What makes people with allergies who are not allergic to cats still sensitive to the animals' allergens? No one is quite sure.

The question deserves "a closer look," said Dr. Marc Riedl, an assistant professor of medicine at the David Geffen School of Medicine at the University of California, Los Angeles. One reason cat allergens may have a wider impact is that these small airborne particles, which can be a quarter of the size of dust mites, "are much more likely to have access to the lung than other allergens," he said. Consequently, cat allergens could have wider effects that have nothing to do with allergic sensitivity per se.

Then there are substances called endotoxins. Endotoxins break down portions of bacteria that in turn stimulate the immune system, Shier explained.

The study raises the question of whether endotoxins -- which have been found at higher levels in cat owners' homes -- might be the cause of increased bronchial responsiveness observed in ostensibly non-cat-allergic people, he said. "There [also] may be some other unknown entity that comes from the cat that may be responsible for triggering the bronchial hyperactivity," he added.

The European study also pointed out gender differences in terms of who is most vulnerable to cat allergy. Among the almost 1,900 randomly selected participants included in the study, men and women turned out to be equally sensitive to cats. However, women had a higher exposure to cat allergens, were more likely currently to own a cat, and were more likely to allow the cat in the bedroom.

Cat ownership also varied by country, ranging from as low as 10 percent of participants in Spain to as high as 35 percent among the British.

More information

There's more on pet allergies at Asthma and Allergy Foundation of America.