Allergy shots don't cure allergies, but they should reduce your symptoms noticeably.
They are best if you have severe allergy symptoms or symptoms that last more than three months every year, says Michael Land, MD. They can also help people who can't take allergy medicines because of side effects or interactions with other medications.
The shots are a form immunotherapy, which retrains your immune system not to overreact to your allergy trigger. Each shot contains a little bit of your allergy trigger, and over time, the dose gets bigger, so that you slowly and safely become less sensitive to that trigger.
In the buildup phase, you'll get the shots once or twice a week for several months. Some people start to feel relief within the first few weeks, though it may take several months.
When you reach your maintenance dose, you'll get a shot every 2 to 4 weeks for 3 to 5 years. Eventually, you may not need the shots at all, unless you move to an area where the pollen is different.
In most cases, allergy shots don't cause side effects, other than redness and slight swelling near the injection site. Because there's a small chance that you could have an allergic reaction, you get allergy shots at a doctor's office and stay there for about 30 minutes afterward.