Allergy and Pets (cont.)

A number of allergy causing factors, such as parental smoking and pets, also were checked. The researchers came up empty. "Two million dollars and nothing to show for it," exclaims Ownby. "Dust mites had no effect that we could find."

Then they thought about some findings in southern Germany that seemed to show that kids raised on farms had a lower incidence of allergies. They went back and looked at their pet questions on the survey.

"It really was surprising," Ownby says. "Being exposed to one dog lowered sensitivity to all allergens. Two dogs had a bigger effect than one dog." The effect of cats in the home was similar, so the researchers combined dogs and cats. They compared kids with no pets, one dog or cat, and two pets (dogs or cats or one of each) -- and found almost a 70% reduction in sensitivity from those with two pets.

One effect, the researchers say, may come from being licked by the pet, which transfers bacteria that changes the child's immune system. It alters it by introducing the child's immune system, which triggers allergies, to substances early.

Ownby is starting an NIH-funded study to follow up with the same kids, who are now 18. They will study more races and ethnic groups this time and factor in the weight of the pet. "Does a 20 pound dog have more of an effect than two 10-pound cats?" he wonders.

Allergists Still Cautious

"The data does not support the idea that people should get pets just to prevent allergies," Smart says. "We have dogs at home. We like pets -- and we see a great value to the family of having pets," he explains. "We have to be careful not to change everything based on one study, though."

Are there things people can do to minimize the allergic potential of a given dog or cat (even a dood)? If a child tends to be allergic, Smart says, you can limit the contact in a reasonable way. Make the bedroom 100% pet-free, he suggests. The child should also wash hands after playing with the animal. The dog or cat should also be washed once a week.

As for air filters, Smart says the value of a home filter for dog dander has not been proven. "There is some evidence these are helpful for cat allergies," he says. A vacuum cleaner with a HEPA device might also be a good idea.

Despite his research that shows pet ownership can cut sensitization, Ownby is hard-line on animals that are causing a bad problem for youngsters. "Keep the pets outside," he says.

Although allergy shots can help some, he explains, once the person is showing signs of an allergy, avoidance is best.

"Sometimes," agrees Smart, "a child is really harmed by being around an animal. It can affect sleep quality or school work."

Star Lawrence is a medical journalist based in the Phoenix area.

Published Sept. 13, 2004.

SOURCES: Karen Can, labradoodle owner, Broomall, Penn. Dee Gerrish, owner, Lake Ridge Kennels, Cleveland, N.C. Brian A. Smart, MD, allergist, DuPage Medical Group, Glen Ellyn, Ill. Dennis R. Ownby, MD, head, section on allergy and immunology, Medical College of Georgia, Augusta, Ga. Ownby DR, Cole CJ, Peterson EL, "Exposure to Dogs and Cats in the First Year of Life and Risk of Allergic Sensitization at 6 to 7 Years of Age," JAMA, Aug. 28, 2002; vol 288: No 8.

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