Allergen immunotherapy (AIT) is a treatment involving the administration of increasing doses of clinically relevant allergens to patients who have allergic disease. The effect of AIT has been clinically confirmed in the cases of allergic asthma, allergic rhinitis, etc… AIT shows subtypes such as subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT). Allergens are subcutaneously injected in SCIT, or placed sublingually then swallowed in SLIT.

AIT differs from pharmacotherapy in that the therapy can improve the natural course of asthma and allergies, it is a unique therapy which is capable to change the natural evolution of allergic diseases. With this treatment mode, allergens are given to patients in repeated and increasing doses to provide immune tolerance.
The effectiveness of both subcutaneous (SCIT) and sublingual (SLIT) immunotherapy is documented for both perennial and seasonal allergic respiratory disease by systematic reviews and meta-analyses. For almost 100 years now, subcutaneous route has been used to treat allergic diseases; however, there are many studies to confirm the administration of SLIT because of discomfort of repeated injections and higher risk of adverse reactions.

What happens when you undergo this process of Immunotherapy ?
It is a simple and cost-effective procedure performed by an immunologist. The entire procedure is broken down into two steps. They are:
PREPARATION :The doctor will first begin by testing for allergies. Allergy testing involves your doctor making a small prick on your arm with various allergens to find the one that causes a reaction.

PROCEDURE : Once the doctor has found the allergen, he will start giving you allergy shots. There are two phases in this process – the buildup phase and the maintenance phase.
Buildup phase: It is the most crucial phase and requires time and commitment. It lasts for up to six months. You may receive an allergy shot once a week during the first few weeks that may later be reduced to one shot every two weeks. This phase helps your body adjust to the allergens and develop tolerance towards them.
In a few cases, the buildup phase may be completed more quickly by administering a higher number of shots to the patient during each visit. This is done to relieve your symptoms immediately and reduce the amount of time required by your body to reach the maintenance phase. However, it is risky and may cause you to develop a severe reaction.

MAINTENANCE PHASE : After the buildup phase, your doctor will check whether your body has grown accustomed to the allergens. He will do so based on your body’s reaction to the shots. Once he feels that your body has adjusted, you will enter the maintenance phase. In this phase, you will be administered the allergy shots once or twice a month. This phase generally lasts for three to five years. Your doctor will advise you not to skip a single shot during this time as it may disrupt the treatment course.
Your doctor will ask you to stay at the hospital or the clinic for about 30 minutes after administering the shot. This is to monitor if you are having an allergic reaction.