What is allergy shots?

When you get an allergy shot, your allergist or doctor injects small doses of substances that you are allergic to (allergens) under your skin. This helps your body "get used to" the allergen, which can reduce or prevent symptoms.

At first, you may need to get allergy shots once a week and then once a month. It may take up to a full year of shots before you see any change in your symptoms.

The allergy shot may cause mild problems, such as soreness, redness, warmth, or swelling on the arm where you got the shot. It may also cause itching, hives, or a rash that spreads to other parts of your body.

• Do not smoke or allow others to smoke around you. Smoking makes allergies worse. If you need help quitting, talk to your doctor about stop-smoking programs and medicines. These can increase your chances of quitting for good.
• If there is a lot of pollution, pollen, or dust outside, stay inside and keep the windows closed. Use an air conditioner when it's hot outside, and use an air filter in your home.
• If dust or dust mites trigger your asthma, decrease the dust around your bed:
  • Wash sheets, pillowcases, and other bedding in hot water every week.
  • Use dust-proof covers for pillows, duvets, and mattresses. Avoid plastic covers, because they tear easily and do not "breathe." Wash as instructed on the label.
  • Do not use any blankets and pillows that you do not need.
  • Use blankets that you can wash in your washing machine.
  • Consider removing drapes and carpets, which attract and hold dust, from your bedroom.
• If mold triggers your allergies, get rid of furniture, rugs, and drapes that smell musty. Check for mold under sinks and in the bathroom, attic, and basement. Use a dehumidifier to control mold in these areas.
• If pet dander triggers your allergies, keep pets outside or out of your bedroom. Old carpet and cloth furniture can hold a lot of animal dander. You may need to replace them.
• If your allergies are triggered by cold air, wear a scarf around your face, and breathe through your nose.
• Avoid infections such as COVID-19, colds, and the flu. Wash your hands often. Talk to your doctor about getting a pneumococcal vaccine shot. If you have had one before, ask your doctor whether you need another dose. Get a flu vaccine every year. Stay up to date on your COVID-19 vaccines.

Allergy shots are effective in treating allergic rhinitis and allergic asthma. The shots reduce symptoms in those allergic to pollens, animal dander, dust mites, mold, and cockroaches. Experts do not know how long allergy shots work after you stop getting the shots. Some people may not have their allergies return. Others may have allergies return within a few years.

Although you still need to avoid allergens, you may be able to use less medicine or stop using medicines.

Allergy shots are safe if the shots are given correctly. The most common side effects are redness and warmth at the shot site. Some people may have reactions near where they had the shot, such as itching, hives, or swelling of the skin. More serious but less common side effects include symptoms that affect other parts of the body. Examples are hives, itching, and trouble breathing.

In rare cases, a person may have a severe allergic reaction (anaphylaxis) to the shots. Because of this possibility, the shots are given in a doctor's office or other setting where emergency care can be provided if needed. You must report any delayed reaction that you have to a shot. Late reactions can happen anytime within 24 hours after a shot.

Allergy shots may not be right for you if you:

• Have another condition, such as asthma. You may be more likely to have a severe reaction to the shots. You should have your asthma well controlled before you get allergy shots.
• Have an autoimmune disease, such as lupus.
• Are taking beta-blockers, such as propranolol (Inderal, for example). They are often used to treat heart conditions, glaucoma, migraine headaches, and high blood pressure.
• Are taking ACE inhibitors, such as captopril (Capoten, for example) or lisinopril (Prinivil, Zestril, or Zestoretic, for example). These are often prescribed for high blood pressure and a variety of heart conditions. Talk to your doctor first about the potential risks of allergy shots.
• Are not able to communicate about reactions to shots. Most doctors don't give allergy shots to children younger than age 5.

Allergy shots are usually given in a doctor's office. It is normal to stay in the doctor's office for a short time after getting an allergy shot to be watched for possible serious reactions to the injected insect venom.

Redness and warmth at the shot site are common. But they'll go away after a short time.

At first, a small amount of allergens is used. You get the shots once or twice a week. The amount of allergen is gradually increased.

After about 4 to 6 months of weekly shots, you will likely be getting the best amount of allergen in the shot. This is called the maintenance dose. When you reach the maintenance dose, you get the same dose in shots every 2 to 4 weeks for the next 4 to 6 months.

The period between shots is gradually increased to about a month. And the dose usually stays the same each month. After 1 year of maintenance, your allergist will check to see if you have fewer or less severe symptoms. If your allergy symptoms have not changed, you will no longer get the shots. If your symptoms have improved, you may keep getting monthly shots for up to 3 to 5 years.

Allergy shots can reduce your reaction to allergens, which can result in fewer or less severe symptoms. They may also prevent children who have allergic rhinitis from getting asthma. Recommendations on when to get allergy shots vary, but in general you and your doctor may consider them when:

• Allergy symptoms are severe enough that the benefit from the shots outweighs the expense and the time spent getting the shots.
• You are allergic to only a few substances, and they are hard to avoid.
• Avoiding allergens and using medicine do not control symptoms, or you have to take medicine all the time to control symptoms.
• Side effects of medicines are a problem.
• You want a treatment for the cause of your allergy, rather than treatment for just the symptoms.
• You have another condition that is being affected by allergic rhinitis, such as asthma.
• You want to lower the chance that you will develop asthma.