Allergy Shots Could Prevent Asthma

From the WebMD Archives

Aug. 21, 2000 -- Hay fever and asthma often go hand in hand, and a new study shows that allergy shots may be able to wipe out both of them. Researchers have found that children who are given allergy shots are far less likely to go on to develop asthma.

With the shots, "we see encouraging results, with a significant reduction in the number of patients developing asthma," researcher Lars Jacobsen, MD, director of medical communication and clinical relations for ALK-Abello Group of Hoersholm, Denmark, tells WebMD.

Jacobsen and colleagues wanted to see if allergy shots could help prevent the development of asthma, since about one third of people with hay fever also have asthma. The researchers recently presented their findings at an international conference in New York sponsored by the American College of Allergy, Asthma and Immunology.

So far, only the results of the first three years of the 10-year study -- involving 208 children ages 6 to 14 with allergies to birch, grass pollen, or both -- are available. The children received either allergy shots or treatment with standard medications to control their allergy symptoms.

"When we compare these groups, we see at least a 50% reduction in the number of children that have asthma" among those who got the shots, Jacobsen tells WebMD. "Ask any allergist who has done this treatment for 20 years, and the immediate reaction is, 'I knew it. I had this feeling.' They all have this feeling, but no one had ever tried to show it."

While the link between allergic hay fever and asthma "has long been known, this is the first large study to suggest that allergy shots not only help rid patients of hay fever symptoms, but also may prevent them from developing into the more serious disease of asthma," says Jacobsen. Approximately 80% of all asthma in children and 50% of asthma in adults is caused by allergies.

Symptoms of respiratory allergies -- often called hay fever -- typically include watery eyes, sneezing, nasal congestion, and wheezing. Attacks are commonly trigged by such substances as plant pollens, dust, and pet dander. Asthma shows itself as recurring attacks of breathing difficulties, coughing, wheezing and chest tightness. In addition to the allergy-causing substances, known as allergens, other triggers for asthma attacks may include exercise, cold air, and pollution.

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Allergy shots work on the theory that injecting small quantities of the allergen creates an immune reaction in the body. When patients get the shots, their bodies start to make antibodies that block the body's reaction to the allergen, thus reducing or eliminating the allergic reaction.

Very often, says Jacobsen, doctors overlook the allergy trigger in treating asthma "because many of these patients, depending on which doctor and which specialty they go to, may or may not get an allergy test." That means these patients are left to be treated with drugs that only treat the symptoms, such as steroids, inhalers, and sprays.

"Overall, this study is consistent with what's been published before and with clinical experience of allergists -- and he's probably right," David Rosenstreich, MD, director of allergy and immunology at Albert Einstein School of Medicine in the Bronx, N.Y., tells WebMD.

But the preventive effects of allergy shots are likely limited to seasonal allergies, he says. "In studies of asthma, people with chronic allergies [such as allergies to dust] don't benefit from allergy shots," Rosenstreich tells WebMD. "Shots work best when you have a defined exposure for a relatively short period of time, like tree pollen season or grass pollen season."

He points to another study "showing that overall, allergy shots do work for asthma. [But] one well-known study from Johns Hopkins, looking at children with allergy shots with a number of different allergens, showed that it didn't help. So there's a lot of controversy in this field."

Jacobsen's study was funded by the ALK-Abello Group of Hoersholm, Denmark, a company that produces allergen extracts for allergy shots.

For more information from WebMD, visit our Diseases and Conditions page on Asthma.

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