By Karla Harby
NEW YORK, Aug 21 (Reuters Health) - Children who receive allergy shots for
their hay fever appear to be much less likely to develop asthma later on,
according to research conducted in Europe and presented Sunday at a consensus
conference sponsored by the American College of Allergy, Asthma & Immunology and
St. Luke's-Roosevelt Hospital Center, New York.
In a five-year study of 208 children age 6 to 14 years who had hay fever,
those who did not receive allergy shots were more than 2.5 times more likely to
develop asthma than children who were given allergy shots.
The shots also helped the patients' hay fever symptoms, according to Dr.
Lars Jacobsen of the ALK-Abello Group, Hoersholm, Denmark. "We saw significant
improvement during (the hay fever) season, and even more pronounced improvement
outside season, in the winter time," he said.
Hay fever is an allergic reaction, including sneezing, itching, watery eyes
and nasal congestion, which is caused by sensitivity to grasses or tree pollen
or other substances. Asthma is a chronic respiratory disease characterized by
coughing, wheezing, and a shortness of breath that is not caused by having a
cold or the flu.
Allergy shots, also called allergy immunization or specific immunotherapy,
work by interfering with the body's over-reaction to harmless foreign proteins.
Small quantities of the allergy-causing substances are injected at regular
intervals, gradually causing the body to make antibodies that block the
patient's allergic reaction. In most cases, the patient receives injections
regularly for at least a year, and sometimes for as long as three years.
Exactly how allergy shots prevent asthma is unknown. The most common
triggers of hay fever are cats, cockroaches, dust mites, mold and pollen from
ragweed, grasses and trees. These same allergens also cause asthma attacks in
susceptible people, and it is common to have both diseases. The researchers
speculate that allergy shots not only reduce reactions to specific allergens,
such as cat dander, but may also cause a basic shift in the patient's underlying
immunological response.
The study involved researchers in Austria, Denmark, Finland, Germany and
Sweden.
