IMMUNOTHERAPY (ALLERGY SHOTS)

Immunotherapy (allergy shots) are used to decrease your sensitivity to allergens so that exposure to pollens, dust mites, molds, and other sources of allergen will result in fewer symptoms. This does not mean that allergy shots are a substitute for avoidance because shots work best when exposure to the offending allergen is reduced

Improvement should not be expected immediately. It usually requires at least 6 to 12 months for the benefits of immunotherapy to occur. Always remember that with effective immunotherapy symptoms should improve, but may not go away completely. The goal is to make patients feel better and become less reliant on medications.

Allergy injections are begun at a very low dose. This dose is gradually increased until therapeutic dose (often called the “maintenance dose”) is reached. This dose may differ from patient to patient. Shots are initially given every 3-7 days while the dose is being increased. This frequency reduces the chance of reactions and permits the maintenance dose to be reach in a reasonable amount of time. After the maintenance dose has been reached, injections are usually given every 2 weeks for several years. The goal is to eventually spread the shots out to every 3-4 weeks over a period of 4-5 years. At that time the allergist, the patient, and the patient’s primary care physician will make a joint decision to continue or discontinue immunotherapy. A small percentage of patients may see no improvement in symptoms after 12 to 18 months. In this case immunotherapy is discontinued.

It usually takes 4-6 months to reach a maintenance dose. This time may be longer if large local reactions occur along the way. The time will also be prolonged if the injections are not received on a regular basis. For this reason, it is important that the schedule for giving shots is followed.

Allergy injections should be administered at a medical facility with a physician present so that treatment can be given if a reaction to an allergy shot occurs. As an added precaution, there is a waiting period of 20-30 minutes after the injection. If a significant reaction does occur, the dose of the extract given will be reduced and cautiously increased again provided that there are no further reactions. Medical facilities should be equipped to treat allergy injection reactions.

In general, reactions to allergy shots occur in about one per thousand patients and most are mild and easily treated. The incidence of fatalities based on shots given is less than one in a million. Nevertheless, it’s important to be in good health on the day of the injection and in the medical facility for the required time. Reduced lung function in asthma patients is associated with increased risk for acute wheezing. As a result, peak flow tests should be measured before and 20 minutes after each injection in children or adults with asthma.