Doctors may recommend allergy shots or under-the-tongue drops to their patients, but most don't start the treatments, reports a new study.
Researchers also found that among patients who do begin so-called allergen immunotherapy, most don't complete the full course of therapy, which takes years.
The study looked at people with allergic rhinitis, which includes seasonal allergies and sensitivities to dust mites and pet dander, for instance. It is one of the most common reasons people go to the doctor: up to one third of adults and 40% of kids suffer from a runny nose, sneezing and watery eyes in the presence of particular allergens.
Best allergy treatment
When symptoms aren't fully managed by allergy medications, doctors may suggest a course of allergen immunotherapy, which can include getting regular allergy shots or taking under-the-tongue ("sublingual") drops at home for three to five years.
Read: Diagnosing allergies
"It is, I guess unfortunately, the best kept secret amongst allergists because it is the best allergy treatment that we have available and the only treatment that is a disease modifier," Dr Robert Anolik told Reuters Health.
Patients on the treatments can help control their symptoms and those that use immunotherapy for enough time may see long-term benefits, he said.
Anolik, from Allergy and Asthma Specialists of Blue Bell, Pennsylvania, led the study. His team's findings were published in the Annals of Allergy, Asthma and Immunology.
The researchers reviewed the medical records of patients with allergic rhinitis who doctors had recommended should start allergy shots or sublingual drops between January 2005 and June 2011. The patients were all from one allergy clinic in Pennsylvania.
Out of 8 790 patients, only 36% chose to start allergen immunotherapy. About three quarters of them chose allergy shots and the rest opted for sublingual drops.
Reasons for quitting
People who were sensitive to a greater number of allergens were more likely to try one of the therapies.
Read: Top 10 allergy triggers
Among patients who started the allergen immunotherapy, 40% quit before completing three years of treatment and most quit before five years.
In general, patients kept using allergy shots longer than drops and children continued either treatment longer than adults.
Most patients did not give a specific reason for stopping treatment. Others stopped because of the cost of treatment, side effects or lack of benefit. About half of those who stopped taking the drops did so because they didn't like the taste.
"Immunotherapy has been around for 90 years so there's enormous experience with it and I think pretty much that what they wrote about is fairly standard," Dr David Rosenstreich told Reuters Health.
Rosenstreich directs the Division of Allergy and Immunology at Montefiore Medical Centre in Bronx, New York. He wasn't involved in the study.
"People often prefer getting the drops under the tongue, but surprisingly they tend to drop out from that more often," he said. "People who are on the injections tend to actually – surprisingly – stay on them more consistently than people who are on the drops."
Large psychological benefit
Rosenstreich said patients who take the drops don't have the same supervision from their doctor, which offers additional benefit beyond the injections.
"You're seeing a health professional on a regular basis and at the same time you're getting your medications renewed and if you're having problems, they're being taken care of and there's a large psychological benefit also from being seen frequently by a health professional."
"I think an effort has to be made from physicians, through education and through social media, so that once patients start to keep them involved," Anolik said.
He said his office uses a combination of emails and text messages to remind patients that their allergy shots are due or to keep up with their allergy drops.
Both Rosenstreich and Anolik mentioned two new immunotherapy tablets that are available for treating grass and ragweed allergies, Ragwitek and Grastek.
Anolik is hopeful that awareness of the new sublingual products will help the general public learn more about immunotherapy in general.
"With the power of large pharmaceutical organisations to market and advertise I am hopeful that more and more people will be aware of immunotherapy as an option. And then our goal is to match up the patients with the appropriate therapy," he said.
The study was funded by Merck, which markets both new products.
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Image: Allergy shot from Shutterstock