Image for desensitization article Desensitization Treatments

Those of us looking for alternatives to chronic itchy eyes and runny noses may have heard of some allergy treatments that don’t involve drugs or weekly allergy shots. Two methods gaining popularity are enzyme potentiated desensitization and low dose immunotherapy.

Enzyme Potentiated Desensitization

Enzyme potentiated desensitization (EPD) is used in England. Some doctors in the US also tout its benefits. Like conventional allergy shots, EPD tries to stimulate a patient’s own immune system to build up an appropriate response to the offending substance (allergen). EPD differs from conventional allergy shots, however, by using tiny amounts of the allergen in combination with an enzyme called beta-glucuronidase. This combination solution is given as a shot into the skin once every two months for 18 to 24 months. Conventional allergy shots are given initially about once a week then continued about once a month for several years.

Using EPD

Jack Pulec, MD, an ear, nose, and throat doctor in Los Angeles, has treated some patients with EPD. He feels that EPD is extremely safe because it uses the same concentrations of allergens that one might breathe or come into contact with during everyday situations. “No one has ever had any serious problems with any EPD treatment in terms of dying or getting a severe reaction,” he says. He also believes EPD can help patients with food allergies and reactions to smells like soaps or paint that conventional allergy shots can’t help.

Low Dose Immunotherapy

Low dose immunotherapy (also known as the Rinkel method) is similar to EPD in that it uses very small amounts of the allergen, although not necessarily in combination with the enzyme beta-glucuronidase.

But Do These Treatments Work?

Although these treatments haven’t hurt anyone, and some people claim that their symptoms improved, the true effectiveness remains questionable. “EPD has not been proven in any good controlled studies and it just mechanistically doesn’t make sense,” says Linda Cox, MD, an allergist and member of the American Academy of Allergy, Asthma, and Immunology. A United States study begun in the 1990s to prove the effectiveness of EPD never completed its investigation. Meanwhile, in England, researchers recently tested EPD in people with severe summer hay fever. They found that it worked no better than a placebo.

In January 2003, the American Academy of Allergy, Asthma, and Immunology released guidelines for the practice of desensitization and immunotherapy. These guidelines stated that EPD and low dose immunotherapy are not effective and not recommended. Most health insurers will not cover these types of treatments.

What About Conventional Allergy Shots?

Many scientific studies show convincing evidence that allergy shots, called “allergy vaccines” by allergist physicians, do work. Allergy vaccines can effectively reduce symptoms from hay fever (also known as allergic rhinitis), allergic asthma , and bee stings . Allergy vaccines work by slowly introducing the patient to more and more of the allergen. The problem being that this treatment is time consuming. The whole process includes an initial build-up phase with weekly injections for several months, then monthly maintenance injections for several years. After each injection, doctors may ask patients to remain in the physician’s office for 20-30 minutes to watch for any side effects. However, serious allergic reactions to the shots are extremely rare, says Cox.

Research on Easier and Faster Methods

American doctors know that many people are turned off by the time commitment required for conventional allergy shots. So, investigators are looking for easier and faster ways to do immunotherapy and desensitization. For example, in Europe, instead of using shots, doctors give allergy vaccines by placing the allergen solution under the tongue and letting it absorb into the body. “This is gaining a lot of popularity in Europe,” says Cox, “and it looks like it is effective in both allergic rhinitis and asthma.” Several double-blind, placebo-controlled studies indicate that sublingual immunotherapy (SLI) can improve symptoms of allergic rhinitis when the offending allergens are known. A great advantage to this method is that people can do it themselves at home and not have to go into their doctors’ offices every week or month. This method is increasingly available in the US, as well.

Other investigators are looking at ways to speed up the whole desensitization process. “If we can get people up to their maintenance dose in one week or a couple of weeks [instead of several months],” says Cox, “it will make it much more palatable to the general public.” But research on these methods is still ongoing.

For now, people with bothersome allergies should consult their doctors about the pros and cons of all the available effective strategies.