Allergic diseases affect approximately 20 percent of the U.S. population. Medications offer temporary relief, but no cure. Long term medication use is unsatisfactory for many patients because of side effects. Therefore, many seek other options, including acupuncture, herbal remedies and immunotherapy.
Research continues into allergy treatment by immunotherapy. The idea is to retrain the immune system to tolerate, or ignore, substances such as pollens and peanut proteins that should be harmless. The current gold standard is subcutaneous immunotherapy, which requires weekly injections for typically four to six months. Clinical trials are underway for therapies that offer comparable results without so many needle sticks. A recent review from the University of California San Diego shows us what's in the works.
Current subcutaneous immunotherapy (allergy shots) starts with a dosage diluted 10,000 to 100,000 times from the target dose of the allergen. The strength of the shots is increased very slowly, to minimize the danger of adverse effects. With this regimen, approximately 0.1 percent of patients experience systemic allergic reactions that require epinephrine.
Sublingual immunotherapy has been used mostly in Europe for the last 20 years, but is still considered investigational in the U.S. Tablets with the allergen of interest are kept under the tongue for one to two minutes and then swallowed. This method has been used either seasonally, for spring or fall pollen allergies, or throughout the year for perennial allergens such as dust mites. In published studies of 3,984 patients, there were 14 reported serious adverse effects, including anaphylaxis and asthma exacerbation. According to reference one, this is a better safety record than allergy shots. So far, sublingual therapy appears to be less effective than shots, but the author recommends studies to compare the two options directly.
Toll like receptor-9 vaccines offer a more high-tech approach. In studies with ragweed pollen allergy, subjects were protected from symptoms through two ragweed seasons with only six weekly injections.