Immunotherapy for Allergies
Immunotherapy is an extended treatment for allergies that uses the administration of small, gradually increasing, doses of the allergen causing the problem. As the dosages increase, the patient develops an increased tolerance for the offending substance. Immunotherapy works to bolster the immune system without triggering an allergic reaction.
Reasons for Immunotherapy
While many patients can control their allergic symptoms by altering their habits to avoid the allergen or by taking over-the-counter or prescribed medication, for other patients, immunotherapy is a good option. Reasons for immunotherapy include:
- Having persistent allergic symptoms for more than 3 months per year
- Have allergic symptoms that are not alleviated by medication
- Being susceptible to anaphylaxis, a life-threatening allergic reaction
Immunotherapy can relieve allergy symptoms and help reduce the frequency of reactions in patients allergic to common allergens, such as pollen, dust mites, mold, and animal dander. Even more importantly, immunotherapy can reduce the severity of allergic reactions in patients whose lives are put at risk by exposure to particular allergens, such as:
- Bee venom
- Certain medications, especially penicillin
- Foods, such as peanuts, tree nuts, shellfish, milk or eggs
More rarely, patients may have an anaphylactic reaction to latex or medications used in anesthesia. For patients whose allergies are severe enough to interfere with daily life, or in patients whose allergic reactions are life-threatening, immunotherapy may be a desired, or necessary, treatment.
Preparation for Immunotherapy
Patients may be advised not to exercise for a couple of hours before and after treatments, and to stop taking certain medications or herbal supplements. After each immunotherapy visit, the patient is instructed to wait for about 30 minutes to make sure there is no severe reaction to treatment. Patients who are pregnant should consult with their obstetricians before undergoing immunotherapy for their allergic symptoms.
The Immunotherapy Procedure
A course of immunotherapy typically begins with the injection of minute quantities of the allergen into the patient's arm once a week. Gradually, these doses are increased. In a month or two, the patient is usually receiving the optimal amount of allergen in the injection, enough to demonstrate sufficient tolerance to allow the patient limited exposure to the allergen without developing symptoms. This is referred to as a maintenance dose.
Once the maintenance dose is reached, the patient will receive the same dose with decreasing frequency. That same dose may be administered every 2 weeks for about 6 months. At that time, the period between injections is increased to about 4 weeks. Patients may be kept on a maintenance dose once a month for up to 5 years to help them retain at least partial immunity to the irritating allergens.
In some instances, immunology for allergens may be administered more intensively, every few hours instead of every week, reaching the maintenance dose much more quickly. This variety of treatment is called cluster, or rush, immunology and must be administered under close monitoring since the risk of systemic reaction is much greater.
Risks of Immunotherapy
Immunotherapy is a common form of treatment for allergies, one considered very safe. Usually, when a patient has an injection-related reaction, the injection site reddens, feels warm or swells slightly. These types of reactions can occur right away or during the next few hours. Some patients may experience the same symptoms that they get when exposed to certain allergens.
In rare cases, immunotherapy causes an anaphylactic reaction. It almost always take place within 30 minutes of receiving the injection, which is why a patient is asked to remain in the office for that period of time. If a severe reaction occurs, immediate medical care is required.
For patients whose allergies are severe enough to interfere with daily life, or in patients whose allergic reactions are life-threatening, immunotherapy may be a desired, or necessary, treatment.