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How do Allergy Shots Work

In a healthy, normal immune system, the body utilizes white blood cells, proteins and antigens to ward off any offending material. Sometimes the response system goes into overdrive and a person experiences an abnormal response to something in the environment that is typically a harmless substance. This is called hypersensitivity. Depending on the type of allergen and its location, the body responds in several ways. These generally include: watery eyes, itchiness, tightening of the throat, hoarseness, redness, swelling and in some severe cases anaphylactic shock leading to death.

What is an Allergic Response?

When the body is exposed to the allergen, a signal is sent that an antibody called immunoglobulin E (IgE) is needed. If the body has the right type of antibody, it will bind to the allergen along with a white blood cell and carry it out into the bloodstream where it will eventually be filtered out of the body. Usually an allergic reaction does not occur with a one-time minimal exposure to the allergen. However, the next time the same substance enters the body, the body “remembers” that it needed the IgE antibodies. These antibodies are ready to attack the foreign body by assaulting it with histamines and prostaglandins that cause swelling and inflammation.

Allergy shots, also referred to as allergic immunotherapy works by exposing the body to small amounts of the allergen and condition the body to “forget” to send IgE antibodies to the site. The body is tricked into thinking that it isn’t allergic after all.

Before You Begin

In order to determine whether a person would benefit from allergy shots, a doctor will first conduct a series of blood tests as well as take a personal medical history. Sometimes a doctor will perform what’s called a “scratch test” to see which classifications of allergens illicit the biggest response on the skin surface.


We live in a world that is full of allergens. One way to cope with allergies, especially airborne allergens is to undergo immunotherapy. This process is sometimes called desensitization. By exposing the body to dilute amounts of known allergens, the hope is that the body will decide not to react in an allergic manner. The most common allergens for which people get shots are dust mites, animal dander, and insect bites. Treating for food allergies is too complex; the patient is advised to simply avoid the foods that trigger an allergic response.

Ideally the shots should be given every 2 to 6 weeks. It typically takes 3 or 4 years before a person is successfully immunized against common allergens. The time commitments, not to mention the cost of the shots themselves are a common deterrent. . Many people experience the same amount of relief from over-the-counter allergy remedies as they would with the expensive immunotherapy.