Allergen Immunotherapy (AIT)

AIT, also known as desensitisation, is available to treat allergic rhinitis (hay fever) that has not responded well to intranasal corticosteroid nasal spray (INCS) treatment.

AIT has been used for more than 100 years and is a proven treatment providing long-term relief for allergic rhinitis. The aim of AIT is to help people react less to their trigger allergens that cause symptoms (such as grass pollen or dust mites). This means having no, or fewer, symptoms and a better quality of life.

AIT can only be prescribed by an allergy specialist so you will need a referral from your GP. Some AIT is registered for use in Australia, and some is not. Speak with your allergy specialist. More information is available at Allergen immunotherapy availability – Australasian Society of Clinical Immunology and Allergy (ASCIA).

This treatment usually starts to work within a few months, but must continue for three to five years. It is available as injections given weekly to monthly, or daily as drops, or as a wafer or tablet placed under the tongue.

After undergoing a full course of treatment, many people are less reactive to the trigger allergen with fewer or no symptoms. Studies have shown the benefit of this treatment lasts several years after completing the course.

AIT may also benefit people with persistent, severe allergic conjunctivitis. However, relief of eye symptoms takes longer than nasal symptoms.

Who can benefit from AIT?

AIT can benefit many people including;

• Those who have severe symptoms that are not being controlled by over the counter and prescribed medications.
• Those who wish to reduce the need for long term antihistamines and nasal sprays.
• those who find it difficult to avoid the allergen they are allergic to (such as dust mites and grass pollens).
• Those who do not wish to avoid the trigger, such as those working with animals or who want a pet but are allergic to them.

Those wanting to know more about AIT should speak with their doctor. For detailed advice and potential treatment, ask for a referral to a medical specialist with experience in allergy and AIT. In those with severe asthma, the option of immunotherapy needs to be carefully assessed with medical specialist advice. A medical specialist may carefully progress AIT in people with asthma as it may improve asthma control.

Treatment in women who are pregnant or planning a pregnancy should not be started, although it can be continued if a woman is on AIT and then becomes pregnant. AIT can be continued when breastfeeding.

AIT treatment is not common in children under five years of age, as often, they are not cooperative.

How is AIT delivered?

AIT can be given using different methods including by injection (sub-cutaneous immunotherapy or SCIT) or by spray, tablet or drops taken under the tongue before being swallowed (sub-lingual immunotherapy or SLIT).

Subcutaneous (injection) Therapy (SCIT)

• AIT injected just under the skin will usually be given via a small needle, starting with a very low dose and increasing gradually until a dose decided by your medical specialist (maintenance dose) is reached.
• Once a maintenance dose is reached, the injections will usually be given monthly, but this may vary depending on the doctor and the person. The injections are continued for 3-5 years.
• Some people may experience some redness, itching or swelling at the site of the injection. This can be managed with a non-sedating antihistamine, ice-packs and paracetamol if it is painful.
• A more serious allergic reaction such as anaphylaxis is very uncommon, but possible. The treating doctor will have the person stay in their clinic for about 30 minutes after the injection is given so they can be watched/observed. Injections are not given at home for safety reasons.

SCIT treatments to house dust mite, grass pollens, tree pollen, mould and pets are currently available in Australia.

Sublingual (oral) Therapy (SLIT)

• SLIT is usually taken at home, on a daily basis in the form of a tablet, spray or liquid.
• AIT SLIT treatment usually starts at a small dose and you normally reach a daily maintenance dose within a few days.
• Once maintenance dose is reached, treatment is continued daily for 3-5 years
• People may experience local mild allergic reactions such as an itchy mouth or throat during the early treatment phase. These reactions usually disappear with time. They can also be managed by a non-sedating antihistamine.
• If an individual experiences an allergic reaction that is more than a mild reaction, such as having trouble swallowing or breathing, they are to discontinue treatment immediately and contact their treating doctor. If they are concerned about serious symptoms like difficulty breathing or throat swelling, call triple zero (000) for an ambulance and seek medical attention. Severe reactions to SLIT are rare.

SLIT treatments to help manage hay fever are currently available in Australia and include treatments for grass pollens, tree pollens and house dust mite.

What is the cost of AIT?

Always speak with your doctor about the cost of AIT. A private health fund rebate may be obtained for some registered tablet and injected allergen immunotherapy products. This will depend on the level of private health insurance cover. While AIT is not cheap, ongoing medications and treatments for moderate to severe allergic rhinitis are not cheap either.

How long does AIT treatment take and how long does it last?

AIT involves regularly exposing the person to the trigger allergen that causes their allergy symptoms. Over time, repeated exposure through subcutaneous immunotherapy (SCIT) or sublingual immunotherapy (SLIT)  ‘retrains’ the immune system to become less sensitive to the allergen. ’Retraining’ the immune system with AIT should not be seen as a ’quick fix’ but an opportunity to get better control and long-lasting relief from allergy symptoms over time. After undergoing a full course of treatment, many people are less reactive to the trigger allergen/s with less or no symptoms. People will often see an improvement in symptoms after 4-5 months of treatment. Retraining the immune system to provide long-lasting benefits takes longer. At least 3 years of treatment is needed to make sure the benefits of AIT treatment continue for several years after the person stops the treatment.

It is important that people follow the advice of their treating medical specialist and that they see their medical specialist at regular intervals during treatment. Stopping treatment too early can result in symptoms returning much sooner. If treatment does not work, there may be other reasons that need to be looked into.

ASCIA has FAQs on Immunotherapy – click here.

Always follow the treatment plan as prescribed by your doctor. Contact your doctor if you have any questions or concerns.