Children with grass pollen allergy are prone to develop asthma. Now researchers have shown that seasonal allergy symptoms and the subsequent risk of asthma can be reduced with a type of immune therapy.

The treatment consists of an extract of the major grass pollens administered under the tongue before and during the spring pollen season for three consecutive years.

“Our findings confirm and expand previous findings (showing) that allergy shots can not only improve hay fever symptoms, but also prevent asthma and its possible chronic consequences,” Dr. Samuele E. Burastero from San Raffaele Scientific Institute in Milan told Reuters Health.

Under-the-tongue immunotherapy is a “safe and effective” alternative to injection immunotherapy, the Italian team writes in the Journal of Allergy and Clinical Immunology.

In the study, 113 children between the ages of 5 and 14 who had hay fever limited to grass pollen, but not seasonal asthma, were randomly assigned to standard symptomatic therapy as needed with antihistamines or nasal steroids (the control group) or to sub-lingual immunotherapy.

In the “build-up” phase, immunotherapy was administered starting in mid-February as one drop of pollen extract under the tongue two times per day, ending on the 15th day with five drops. In the maintenance phase, children were given five drops once daily five times per week until the end of June.

Both phases were repeated for each of the three years of the study.

Children in the immunotherapy group used less allergy medication in the second and third years of therapy and tended to have lower allergy symptom scores, according to the team.

And after three years, children in the control group were nearly 4 times more likely than in the immunotherapy group to develop asthma.

“It is now well established that hay fever and asthma are more closely connected than previously believed,” Burastero said, adding that roughly 20 percent of all hay fever patients develop asthma later in life.

With sublingual immunotherapy, “a far better compliance to this safe and effective form of treatment can be expected from children and their parents than with periodical injections,” the researcher predicted. “Thus, larger numbers of patients are expected to take advantage of it.”

SOURCE: Journal of Allergy and Clinical Immunology, October 2004.