What is Allergy Desensitization?

Allergy desensitization is a form of therapy that aims to weaken a patient's allergic reactions by exposing them to gradually-increasing doses of allergens. Through this procedure, patients are believed to naturally develop an immunologic tolerance to the substances to which they are allergic. The allergens are most often introduced into the patient's system via injection, although the treatment may also be administered sublingually. If successful, allergy desensitization therapy can effectively eliminate allergies for five or more years.

This form of therapy operates on the principle that allergies are caused by a malfunctioning immune system. Allergens are innocuous substances mistakenly recognized by an individual's body as disease-causing cells, alerting the immune system to produce the antibody immunoglobulin E (IgE). IgE then bonds with mast cells and basophils in the system, producing chemical substances that cause the allergic reaction.

Through allergy desensitization, doctors attempt to "retrain" the immune system into recognizing allergens as innocuous substances. In initial allergy desensitization treatments, the doses of allergens introduced into the body are so small they do not elicit a response from the immune system. The dosage then increases in small increments, eventually conditioning the immune system to not react to even large doses of the allergen. After up to six months of weekly allergy desensitization treatments, the therapy shifts to monthly maintenance shots over the course of the next few years.

The allergen is introduced into the system through injection or sublingual administration. For example, an individual being treated for a peanut allergy might be injected with allergy shots containing the substance found in peanuts that causes the allergic reaction. Alternatively, the allergen might also be placed underneath the tongue, where it can be absorbed directly through the blood vessels in the area. Sublingual administration is recommended for patients with very low pain thresholds.

Although the exact working mechanisms behind allergy desensitization therapy have yet to be fully discovered, results are generally favorable enough to be encouraging. Most patients report long-term allergy elimination, with the side effects of the treatment being minimal. The most common side effects are minor allergic reactions, which are to be expected when doses of the allergen are introduced into the system. Serious side effects only occur when the patient has a preexisting systemic disease or is taking medication that may interfere with the treatment. It is recommended that any individual considering allergy desensitization treatment first consult his doctor regarding the safety of the procedure.