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Does immunotherapy work for allergies?

Medically reviewed by Sally Chao, MD. Last updated on Aug 2, 2021.

Official answer

by Drugs.com

Yes, for many people, immunotherapy helps to decrease allergy symptoms or provide complete relief.

There are different types of immunotherapy treatments for allergies:

  • Subcutaneous immunotherapy, or “allergy shots,” treat allergic conditions affecting the nose and eyes, ears and lungs, as well as insect sting allergy.
  • Sublingual immunotherapy manages allergies triggered by dust mite, timothy grass, northern grass or ragweed.
  • Oral immunotherapy reduces the severity of the allergic reaction after accidental exposure to peanuts.

Allergy shots

Allergy shots are the longest known, most used and most effective form of allergy immunotherapy.

How does it work?

Allergy shots work like a vaccine. High-dose allergen extracts that trigger allergy symptoms are injected in gradually increasing doses. The goal is that your immune system gets desensitized to the allergen and tolerance is developed. Usually, allergy symptoms are relieved even after treatment is stopped. It may also prevent the development of asthma and new allergies in children.

What type of allergies?

Various allergens are covered by allergy shots. These include trees, grass, mold, house dust, animals and insect stings.

It also covers allergic conditions like allergic rhinitis (hay fever), allergic asthma, conjunctivitis (eye allergy) or allergic otitis media (ear allergy).

How well does it work?

Allergy shots decrease symptoms of many allergies. After stopping the shots, some people enjoy lasting relief from allergy symptoms, while others may relapse. The effectiveness of subcutaneous immunotherapy may be linked to the length of the treatment and the dose of the allergen.

Some factors that may cause the allergy shot to not work include:

  • Inadequate dose of allergen
  • Missing or unidentified allergens
  • High levels of environmental exposure to the allergen or other triggers, like tobacco smoke

How is it given? How often?

It is given as an injection under the skin of your arm. Shots are given in an allergist’s office because of the risk of a severe allergic reaction.

These injections are given in two phases. The first phase is the buildup phase. Injections are given 1 to 2 times a week. Doses are gradually increased until the target dose is reached. It lasts about 3 to 6 months.

The second phase, called the maintenance phase, begins once the target dose is reached. The target dose depends on individual allergen sensitivity and response to the buildup phase. In this phase, the time between the allergy injections is increased to 2 to 4 weeks.

How long does it take to work?

Improvements may be seen as early as the buildup phase, but sometimes it takes as long as 12 months on the maintenance dose to see progress. If the shots are effective, immunotherapy treatment is generally continued for 3 to 5 years.

Who can benefit?

Children and adults can receive allergy shots. It is not typically recommended for children under age five, as younger children may not be able to cooperate with the scheduling. They also may not be able to accurately share any side effects they may be experiencing.

What are the risks/side effects?

A classic reaction is redness and swelling at the injection site. Some people experience increased allergy symptoms such as sneezing, nasal congestion or hives.

There is a small risk of anaphylactic shock from allergy injections. Therefore, it is recommended to wait in your doctor's office for at least 30 minutes after you receive allergy shots. Symptoms of an anaphylactic reaction may include throat swelling, wheezing, chest tightness, nausea and dizziness.

Sublingual immunotherapy

Sublingual immunotherapy (allergy tablets) is a newer form of immunotherapy. It treats allergies at home with under-the-tongue allergen tablets.

What type of allergies?

Allergy tablets target northern grass pollen, timothy grass pollen, dust mites and short ragweed. This also treats allergic rhinitis and conjunctivitis triggered by these allergens.

How does it work?

An allergist must first confirm your sensitivities using allergy testing. Once determined, an allergen extract is given in sequential doses. This increases the tolerance to the allergen and reduces allergic symptoms.

How well does it work?

The effectiveness of allergy tablets to control allergy symptoms is similar to allergy shots. They both provide long-term improvement even after treatment has ended. The limitation of sublingual immunotherapy is that it is only effective for a single allergen. Shots, on the other hand, can provide relief for more than one allergen.

How is it given? How often?

There are two types of sublingual immunotherapy—tablets and drops. The only formulation available in the U.S. is the tablets. The first dose is given in a clinical setting. Afterward, treatment continues at home.

To take, the tablets are kept under your tongue for 1 to 2 minutes and then swallowed. This is prescribed between 3 days a week to as often as daily. Treatment usually lasts 3 to 5 years.

For grass and ragweed allergies, allergy tablets are used before and during the allergy season. For dust mite allergy, the tablets are used year-round.

Who can benefit?

Sublingual immunotherapy can be used in children as young as 5 years old and in adults up to age 65.

What are the risks/side effects?

Sublingual immunotherapy is generally very safe for both adults and children. Common side effects include itching or burning of the mouth or lips or stomach problems. Though rare, severe allergic reactions have been reported.

Oral immunotherapy

Oral immunotherapy refers to feeding an allergic individual an increasing amount of an allergen with the goal of increasing the threshold that triggers a reaction.

What type of allergies?

Oral immunotherapy treats food allergies. There is only one product approved in the U.S. from this class, and it treats peanut allergies.

How does it work?

An allergic individual is fed an increasing amount of an allergen with the goal of increasing the threshold that triggers a reaction. Oral immunotherapy is not a curative therapy. The goal is to provide you protection against accidental exposure to the allergen. Strict avoidance is still the best treatment option for food allergies.

How well does it work?

Peanut, egg and milk oral immunotherapy have been shown to desensitize approximately 60 to 80 percent of patients studied. “Desensitization” is an improvement in the reaction after exposure to the allergen during a food challenge in a research or clinical setting. It is unknown if desensitization will protect you from accidental exposures in a real-world setting.

How is it given? How often?

A small amount is given orally every day. It is initiated in your allergist’s office and continued at home. Doses are gradually increased over time. It requires a long-term commitment, as treatment can last over several months to years and possibly indefinitely.

Who can benefit?

It is approved for use in children ages 4 to 17 years with peanut allergies.

What are the risks/side effects?

The most common side effects involve the gut, with symptoms like abdominal pain, vomiting and cramping. Other side effects include oral itching, rash, hives, swelling, wheezing and anaphylaxis. Some patients have developed eosinophilic esophagitis, a disease of the esophagus that causes difficulty swallowing, vomiting and abdominal pain.

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