I’m Considering Getting an Allergy Shot but Wondering: How Effective Are Immunotherapy Allergy Shots?

An allergy happens when your immune system attacks a substance — called an allergen — that enters your body. People can be allergic to almost anything, from insect stings to medications. Many people are allergic to things in the environment, like plant pollen, mold spores, and dust mites. Other allergens include pet dander and certain foods. 

Allergy symptoms can be mild, such as sneezing or watery eyes. Or they can be very serious in the case of anaphylaxis. The best treatment for allergies is avoiding allergens altogether. This can be difficult, or even impossible, depending on your allergy. Medications can relieve allergy symptoms. But, for some people, medications aren’t enough. In these cases, allergy shots can be the next step. 

Allergy shots are an effective treatment for many people who have allergies. But what are allergy shots, and how do you know if they will work for you? 

What are allergy shots?

Allergy shots are also called subcutaneous immunotherapy (SCIT). Subcutaneous means the shot is given under your skin, unlike vaccine shots, which go in your muscle. Immunotherapy means that the allergy shots are actually training your immune system not to react to something. In this case, that’s an allergen. 

Allergy shots contain small amounts of an allergen. When a person gets an allergy shot, they are injected with the allergen they are allergic to. The goal is to teach the immune system to stop overreacting to that allergen. A trained healthcare provider will give these shots starting with a small dose of the allergen. Over a period of months, the dose will increase. Eventually, the immune system can tolerate a high allergen dose without having a serious reaction. 

Allergy shots begin with a “build-up” phase. During this phase, you will get an allergy shot once every 1 to 3 weeks for several months. Then you will move to the maintenance phase where you get a shot every 4 to 6 weeks. This entire process can take 3 to 5 years. 

Epinephrine

You might have heard of epinephrine. This is a very different type of allergy shot. Epinephrine treats a severe allergic reaction called anaphylaxis. Epinephrine is usually available as an auto-injector, known as an EpiPen. People with a history of severe allergic reactions or prior anaphylaxis should have an EpiPen. Your healthcare provider will determine if you need an EpiPen. 

Alternatives

Sublingual immunotherapy (SLIT) is another type of immunotherapy for allergies. With SLIT, you put a tablet under your tongue and wait for it to dissolve. SLIT is a great way to treat allergies without injections. Unfortunately, SLIT is only effective for ragweed, timothy grass, and dust mite allergies. Allergy shots (SCIT) are available for many allergens.

It is important to keep your EpiPen with you at all times. Make sure you and your household members know how to use it in case of an emergency. Always follow storage instructions for your EpiPen and replace it when it expires.

Are allergy shots effective?

Allergy shots can relieve nose, eye, and throat symptoms. 

Allergy shots work best for allergies caused by:

• Some pollens (from trees, weeds, and grass)

• Dust mites

• Some molds and fungi

• Animal dander (cats and dogs)

• Insect stings (bees, wasps)

Unfortunately, allergy shots do not work for drug, latex, or food allergies.

Allergy shots do not cure allergies. After allergy shots, many people have fewer or no allergy symptoms. For many people, that relief can last for years. Unfortunately, some people do have early relapses of symptoms. Healthcare providers cannot predict who will relapse. But, in these cases, a person can restart allergy shots. 

Who are allergy shots best for?

Not everyone will benefit from allergy shots, even if they have one of the allergies listed above. An allergist will carefully review your case with you to determine if allergy shots are right for you. 

In general, if you have the following conditions allergy shots might help:

• Asthma triggered by allergies

• Allergic rhinitis (allergies that cause itchy or runny nose)

• Allergic conjunctivitis (allergies that cause itchy or watery eyes)

• Insect bite sensitivities

• Eczema that worsens with exposure to dust mites

If you have severe or unstable asthma or your asthma is triggered by smoke exposure, then allergy shots probably won’t work for you. Healthcare providers also recommend against allergy shots if you are pregnant or taking a beta blocker or angiotensin-converting enzyme (ACE) inhibitors. Allergy shots are usually not given to children younger than 5 years old.

Before starting allergy shots, your healthcare provider will first make sure you are using the right medications and doses to treat your allergy. If you still have symptoms, your healthcare provider will order an allergy skin test. An allergy skin test will help confirm your allergy.

To qualify for allergy shots, you must have allergy symptoms after a natural exposure to your allergen and a positive skin test and one of the following:

• Poor response to medication

• Significant side effects to medication 

• A desire to avoid long-term use of medication

Are there side effects with allergy shots?

The most common side effect of allergy shots is a localized reaction. Localized reactions are very common. Between 30% to 80% of people who get allergy shots report a localized reaction. Localized reactions can include redness, swelling, and itching where you received your shot. These reactions can be very small, like the size of a mosquito bite, or quite large. The reaction can start shortly after you receive your shot and may increase in size over several hours. Most reactions last over 24 hours. 

Localized reactions are bothersome but not dangerous. Most people treat localized reactions with ice and Benadryl.

A more serious side effect of allergy shots is anaphylactic reaction. Anaphylaxis is a severe allergy reaction that can be life threatening. This reaction usually happens within 30 minutes of receiving an allergy shot. Every person who gets allergy shots must stay at the office for at least half an hour afterward. A trained healthcare provider will watch you for signs of anaphylaxis. 

Your healthcare provider will give you an EpiPen and instructions on symptoms of anaphylaxis so you can be prepared in case of emergencies. To be safe, always follow your healthcare providers instructions. Tell your provider about previous reactions to allergy shots, new medications you are taking, or changes in your health. 

If you think you are having an anaphylactic reaction, seek help immediately and call 911. 

How do you pay for allergy shots?

Allergy shots might be covered by your health insurance. You may be able to use your flexible savings account (FSA) or health savings account (HSA) to pay for allergy shots. Insurance coverage is variable, but you may be able to use your FSA or HSA pay for allergy shots.

All that said, are allergy shots worth … a shot?

Allergy shots can relieve allergy symptoms. Many people who get allergy shots are able to stop using their allergy medication completely because they no longer have symptoms. Other people report significant improvement in their symptoms and are able to use less medication. This relief can last for several years, but relapses may happen. In these cases, it is possible to restart allergy shots. 

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Written by:

Patricia Pinto-Garcia, MD, MPH

Patricia Pinto-Garcia, MD, MPH, is a medical editor at GoodRx. She is a licensed, board-certified pediatrician with more than a decade of experience in academic medicine.

Reviewed by:

Sophie Vergnaud, MD

Sophie Vergnaud, MD, is the Senior Medical Director for GoodRx Health. An experienced and dedicated pulmonologist and hospitalist, she spent a decade practicing and teaching clinical medicine at academic hospitals throughout London before transitioning to a career in health education and health technology.

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