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By Amy Norton
HealthDay ReporterTUESDAY, March 26 (HealthDay News) -- Spring is here, and so are seasonal allergies. For the millions who suffer from hay fever or asthma in the United States, a new under-the-tongue treatment may hold promise.
Pills and drops designed to desensitize the immune system to allergens could bring some of these allergy patients relief, a new research review finds.
The review, published March 27 in the Journal of the American Medical Association, pulled together 63 studies on so-called sublingual immunotherapy.
The therapy, commonly used in Europe and Asia, essentially allows people to get traditional allergy shots in the form of pills or drops that dissolve under the tongue. The principle is the same: Expose the immune system to extracts of the substance causing a person's allergy -- grass pollen, for example -- until it builds up a tolerance.
Right now, no under-the-tongue allergy products are approved in the United States. But some doctors offer the therapy anyway; they take the extracts approved for allergy shots and give them to patients to use orally.
In the new review, researchers found "strong" evidence that under-the-tongue immunotherapy eased symptoms of allergy-induced asthma: In eight of 13 studies, patients saw more than a 40 percent improvement in symptoms, versus patients who either got a drug-free placebo or standard medication.
The evidence was weaker when it came to nasal allergies. Only nine of 36 studies showed a more than 40 percent drop in symptoms such as congestion, runny nose and itchy eyes.
Still, the majority of studies did show some benefit, said lead researcher Dr. Sandra Lin, an associate professor of otolaryngology at Johns Hopkins University School of Medicine in Baltimore.
Under-the-tongue products are being evaluated for approval by the U.S. Food and Drug Administration (FDA), and those results will be helpful, said Lin.
She said the results from European trials cannot be simply translated to the United States because of differences in the potency of the allergen extracts used.
"We need studies to see what are the most effective doses for U.S. patients," Lin said.
The idea of taking pills instead of getting shots definitely appeals to patients, said Dr. Harold Nelson, an allergy specialist at National Jewish Health in Denver, who wrote an editorial published with the study.
But his advice to U.S. patients was to wait for products to be approved by the FDA.
Even if your doctor offers under-the-tongue immunotherapy, "there's no guarantee" it would be the same as the products studied in clinical trials, Nelson said. He noted that U.S. doctors commonly give a patient a mix of different allergen extracts, because that's how it is done with allergy shots.
But the under-the-tongue products used in clinical trials have contained only a single allergen extract, Nelson said.
