Allergy shots are also called immunotherapy since the goal is to change the way your immune system responds to allergic triggers. The things that you are allergic to are injected into your arm in gradually increasing amounts in order to build up a tolerance to them. Once tolerance develops over several months your symptoms should be greatly reduced.
Most patients start to feel better after a few months as they reach the stronger doses. However, the overall recommended course of allergy shots is typically 3-5 years. You are free to stop the therapy at any time but staying on shots for 3-5 years has been shown to increase the chance for a long-term benefit that persists even after stopping the injections. Staying on shots for less than 3 years usually leads to a recurrence of symptoms after the shots are stopped. Some patients choose to stay on shots even longer than 5 years if they are highly effective.
Traditionally, patients get a weekly shot for about 6 months as the dose is gradually increased. In some cases, faster schedules are utilized to reach the higher doses sooner. Once at the highest dose (what is called the “maintenance dose”) your allergist may elect to space the shots out to less frequent injections. The minimum frequency is usually once a month but some patients have better results with more frequent injections. This can be discussed with your allergist at any time.
The only risk is the possibility of an allergic reaction against the shots. Your shot extract contains all of the things to which you are allergic. There is always a chance that a shot could trigger an allergic reaction. This is not common but does happen once in a while. Even patients who have been on shots for years can still experience a reaction. Reactions are usually mild but on rare occasions can be serious. For this reason shots must always be administered in a medical clinic where a doctor is present and emergency treatment options are available. You also must wait at least 30 minutes after every shot to be sure that no reaction occurs.
Shots are not felt to be a complete cure. But in most cases, your allergies will be significantly reduced. The exact level of improvement can not be predicted but most patients are very pleased with the improvement. Patients feel much better and use less allergy medication.