Healthdirect Free Australian health advice you can count on.

Medical problem? Call 1800 022 222. If you need urgent medical help, call triple zero immediately

healthdirect Australia is a free service where you can talk to a nurse or doctor who can help you know what to do.

beginning of content

Allergen immunotherapy

8-minute read

Key facts

  • Allergen immunotherapy is used to change the way your body reacts to things you are allergic to (allergens).
  • Allergen immunotherapy works by regularly introducing tiny doses of the allergen to the body over several years, so your body can 'get used' to the allergen and learn not to react to it.
  • Allergen immunotherapy is given via injections under the skin, as oral tablets, oral sprays or drops under the tongue.
  • Allergen immunotherapy may be recommended to treat allergy to insect stings, severe hay fever, asthma and sometimes eczema.
  • The greatest risk of allergen immunotherapy is a severe allergic reaction (anaphylaxis) — but this is very rare.

What is allergen immunotherapy?

Allergen immunotherapy is a way to change how your body reacts to things you are allergic to (allergens). Unlike other allergy medicines, which reduce symptoms, immunotherapy is used to treat allergies directly.

Allergen immunotherapy can prevent or reduce allergies by switching off your body's reaction to things that cause allergic reactions. It can take years to work.

An allergic reaction happens when your body's immune system responds to something that is usually harmless. Allergen immunotherapy works by regularly introducing tiny doses of the allergen to the body over several years. The immune system gradually 'switches off' so you don't react to the allergen anymore.

How is allergen immunotherapy given?

Allergen immunotherapy is given via injections under the skin, as oral tablets, oral sprays or drops under the tongue.

  • Injections — a very small dose of the allergen is given with a small needle. These injections don't usually hurt. At first, you usually need weekly injections. The dose is gradually increased over 3 to 6 months, until a steady (maintenance) dose is reached. You will then need regular injections, usually once a month, for several years.
  • Under the tongue (sublingual) — sublingual immunotherapy is given in tablets, sprays or drops. You keep the allergen under your tongue for a few minutes and then swallow it. You can take this type of immunotherapy at home and there is less chance of side effects. This is more expensive and for some types of allergies it isn't as effective as injections.

Symptoms usually start to improve after about 4 to 5 months. During this time, you must keep taking the immunotherapy regularly and work closely with your doctor. It's usually recommended to keep up the treatment for 3 to 5 years to prevent the allergies returning.

While you are having allergen immunotherapy, continue to take your allergy and asthma medicines as usual — your doctor will guide you.

Allergy immunotherapy should always be done under the supervision of a clinical immunologist or allergy specialist.

Which allergies can allergen immunotherapy treat?

Allergen immunotherapy may be recommended to treat:

  • potentially life-threatening allergies to stinging insects like bees, wasps and jack jumper ants
  • hay fever (allergic rhinitis) caused by pollen or dust mite allergy, when symptoms are severe and medicines aren't working well enough
  • asthma, if you know your symptoms are caused by a specific allergen that's hard to avoid
  • eczema (in rare cases)

Allergen immunotherapy is not currently used in Australia to treat food allergies due to limited evidence for its effectiveness, although research into this is ongoing.

Children and adults can have allergen immunotherapy, although it can be hard to get very young children to cooperate. The treatment is also not suitable for people with some medical conditions, such as heart disease.

How successful is allergen immunotherapy?

Allergen immunotherapy has been in use for more than 100 years. Sublingual immunotherapy is a newer treatment that has become much more effective over the past 10 years.

Research shows allergen immunotherapy can reduce the chance of someone having a severe reaction to stinging insects from about 6 in 10 to less than 1 in 10.

Almost everyone with hay fever who has immunotherapy will have improvement in their symptoms. Most people also experience a better quality of life after allergen immunotherapy.

Allergen immunotherapy can have lasting benefits for asthma, if you can identify the allergen responsible for your asthma symptoms. It can also prevent children with hay fever from developing asthma.

What are the risks of allergen immunotherapy?

Some people experience swelling at the site of the injection. The greatest risk is a severe allergic reaction (anaphylaxis), although this is very rare.

Just in case, you will have to stay in the doctor's surgery for 30 minutes after treatment with allergen immunotherapy, and not exercise for a few hours. Taking an antihistamine before treatment may reduce the chance of side effects.

If you have sublingual immunotherapy, you may have a small amount of swelling or itching inside your mouth, or diarrhoea. Serious side effects are rare.

Resources and support

For more information about how allergen immunotherapy works, when it is recommended and how it is given, visit the Australasian Society of Clinical Immunology and Allergy (ASCIA) website.

Visit Allergy Anaphylaxis Australia for information and support on treatment of allergy.

Call healthdirect on 1800 022 222 at any time to speak to a registered nurse (known as NURSE-ON-CALL in Victoria) for more information and advice.

Learn more here about the development and quality assurance of healthdirect content.

Last reviewed: September 2023


Back To Top

Need more information?

These trusted information partners have more on this topic.

Top results

Allergen Immunotherapy FAQs - Australasian Society of Clinical Immunology and Allergy (ASCIA)

Allergen Immunotherapy (AIT) FAQ (Frequently Asked Questions)

Read more on ASCIA – Australasian Society of Clinical Immunology and Allergy website

Immunotherapy for Allergic Rhinitis (Hay Fever) - Allergy & Anaphylaxis Australia

Allergen Immunotherapy (AIT) has been used for over 100 years and is a proven treatment providing long-term relief for hay fever. The aim of AIT is to help people react less to their trigger allergen/s that cause symptoms (such as grass pollen/house dust mite). This means having no/less symptoms and a better quality of life.

Read more on Allergy and Anaphylaxis Australia website

Venom Immunotherapy FAQs - Australasian Society of Clinical Immunology and Allergy (ASCIA)

Venom Immunotherapy (VIT) Frequently Asked Questions (FAQ)

Read more on ASCIA – Australasian Society of Clinical Immunology and Allergy website

Pollen allergy - Australasian Society of Clinical Immunology and Allergy (ASCIA)

Pollen from grasses, weeds or trees can trigger symptoms of hayfever and asthma. Pollen seasons can last for several months and exposure is difficult to avoid.

Read more on ASCIA – Australasian Society of Clinical Immunology and Allergy website

Anaphylaxis | Health and wellbeing | Queensland Government

Anaphylaxis is a severe allergic reaction that can occur when the body comes into contact with a substance to which it is allergic

Read more on Queensland Health website

Allergic Rhinitis (hayfever) - Allergy & Anaphylaxis Australia

Allergic rhinitis (hay fever) is one of the most common allergic conditions affecting 1 in 5 people in Australia. It is caused by the body’s immune system reacting to common allergens in the environment such as pollen, house dust mite, moulds and animal danders (skin cells and fur).

Read more on Allergy and Anaphylaxis Australia website

Anaphylaxis in children and teenagers | Raising Children Network

Anaphylaxis is a severe allergic reaction. It needs urgent medical attention. Children at risk of anaphylaxis must avoid allergens and have an action plan.

Read more on raisingchildren.net.au website

Evidence-based Allergy Tests and Treatments - Australasian Society of Clinical Immunology and Allergy (ASCIA)

ASCIA PC FAST FACTS Evidence-Based vs Non Evidence-Based allergy tests treatments 2023

Read more on ASCIA – Australasian Society of Clinical Immunology and Allergy website

Allergic rhinitis (hay fever)? - Australasian Society of Clinical Immunology and Allergy (ASCIA)

Allergic rhinitis (commonly known as hay fever) affects around 18% of people in Australia and New Zealand. It can affect children and adults.

Read more on ASCIA – Australasian Society of Clinical Immunology and Allergy website

Allergy Treatments - Australasian Society of Clinical Immunology and Allergy (ASCIA)

ASCIA PC FAST FACTS Allergy Treatments 2023

Read more on ASCIA – Australasian Society of Clinical Immunology and Allergy website

Healthdirect 24hr 7 days a week hotline

24 hour health advice you can count on

1800 022 222

Government Accredited with over 140 information partners

We are a government-funded service, providing quality, approved health information and advice

Australian Government, health department logo ACT Government logo New South Wales government, health department logo Northen Territory Government logo Queensland Government logo Government of South Australia, health department logo Tasmanian government logo Victorian government logo Government of Western Australia, health department logo

Healthdirect Australia acknowledges the Traditional Owners of Country throughout Australia and their continuing connection to land, sea and community. We pay our respects to the Traditional Owners and to Elders both past and present.