Oral alternative to allergy shots improves hay fever

A therapy that allows hay fever sufferers to get allergy shots in the form of a tablet or drops can help alleviate symptoms and cut people's reliance on allergy medication, a new research review confirms.

Known as sublingual immunotherapy, the treatment relies on the same principles as traditional allergy shots, but is delivered by tablets or drops that dissolve under the tongue.

Allergy shots may be used for hay fever when antihistamines and other allergy medications do not control a person's symptoms adequately, or for people who want to reduce their reliance on medication.

The shots help prevent hay fever symptoms by exposing people, over time, to small amounts of the pollen to which they are allergic, essentially desensitizing the immune system to the allergen.

Allergy shots are typically given weekly at first, followed by monthly injections over several years. The treatment does not cure hay fever but is generally effective at reducing symptoms. However, inconvenience and discomfort limits patients' willingness to try allergy shots.

Sublingual immunotherapy is an alternative and has become commonly used in Europe, where two tablet-based products against grass-pollen allergies are available: Grazax and Oralair. There are also a number of drop-based products. No sublingual immunotherapy products have yet been approved in the United States, however.

For the new study, reported in the Journal of Allergy and Clinical Immunology, Italian researchers combined the results of 19 clinical trials conducted since 1995 on the effectiveness of immunotherapy tablets and drops against hay fever caused by grass pollen.

The trials lasted anywhere from three months to three years.

Across the studies, which included a total of 2,971 adults and children with grass-pollen allergies, immunotherapy reduced symptoms by about 20 percent to 30 percent, on average. It also allowed patients to reduce their use of antihistamines and other medications.

The researchers, led by Dr. Gabriele Di Lorenzo of the University of Palermo, describe the benefits as "modest."

In an email, Di Lorenzo told Reuters Health that the findings suggest that sublingual immunotherapy is "highly effective in many, but not in all patients." He said that more work is needed to identify which patients might be most likely to benefit.

Dr. Harold Nelson, an allergist at National Jewish Health in Denver, said that the body of evidence indicates that sublingual immunotherapy beats antihistamines and other medications used to control hay fever symptoms.

In an interview, he noted that antihistamines reduce symptoms by about 12 percent to 15 percent, on average. Nasal steroids, another hay fever option, appear to cut symptoms by about 17 percent.

On the other hand, Nelson said, allergy shots appear to outperform the oral versions, with a symptom reduction about twice that of sublingual immunotherapy.