Allergen Immunotherapy (AIT) FAQ (Frequently Asked Questions)
This information should be read and understood before signing the ASCIA consent form, prior to commencing allergen immunotherapy (AIT) to aeroallergens or venoms.
What is allergen immunotherapy?
Allergen immunotherapy changes the way the immune system reacts to allergens, by switching off allergy. AIT involves the regular administration of gradually increasing doses of allergen extracts, usually over a period of years. This results in tolerance to allergens, with fewer or no symptoms. Three years of AIT can result in five to ten years of benefits. Symptoms may return after this time.
What conditions can allergen immunotherapy help?
Venom allergy immunotherapy:
- Is usually recommended for the treatment of potentially life-threatening allergic reactions to venom from stinging insects.
- Is sometimes recommended for the treatment of generalised reactions without dangerous features such as an all over rash.
- Is not recommended for the treatment of large local swellings, even if severe.
- Is often recommended for treatment of allergic rhinitis (hay fever), due to pollen or dust mite allergy (and sometimes asthma) when symptoms are severe.
- Is recommended when the cause is difficult to avoid, such as grass pollen.
- Is recommended when medications don't help or cause adverse side effects, or when people prefer to avoid medications.
What should I expect?
- AIT for insect allergy is given by regular injections for five years in most cases, sometimes longer.
- AIT for aeroallergens can be given by regular injection (subcutaneous), or by daily oral doses (sublingual). It generally takes at least four to six months to improve symptoms. If an improvement in symptoms is seen, recommended treatment duration is three to five years, to reduce the risk of symptoms returning.
- AIT is not like homeopathy. Homeopathy claims to cure a variety of medical conditions using extremely weak extracts, a claim for which there is no scientific evidence. By contrast, AIT only works if high doses are used.
- Allergy medicines can still be used to help manage symptoms while undergoing AIT.
How often are allergen immunotherapy injections given?
- AIT injections start with a very low dose. A small needle is used which may be uncomfortable, but not very painful. The dose is gradually increased on a regular (usually weekly) basis, until an effective maintenance dose is reached.
- Once the maintenance dose is reached, injections are usually administered monthly in a medical facility under supervision. Patients should stay at the medical facility for 30-45 minutes after an AIT injection has been given.
- For some patients who are not tolerating AIT injections, sublingual immunotherapy may be an option.
How often is sublingual allergen immunotherapy taken?
Sublingual allergen immunotherapy extracts are usually taken on a daily basis.
Common methods for taking the allergen extracts:
- Take in the morning on an empty stomach.
- Keep the drops or tablet under the tongue for at least two minutes, then swallow.
- Do not eat/drink anything for 15 minutes.
- Avoid foods that may cut the tongue and increase the likelihood of mouth irritation from the extracts.
- If you forget to take them in the morning, continue treatment the next morning at the usual dosage.
Are there any potential reactions to allergen immunotherapy injections?
Localised swelling at the site of the injection can be treated with non-sedating oral antihistamines or ice packs and if painful, Paracetamol.
More serious reactions (such as anaphylaxis) are uncommon. However, predicting who might have serious reactions is difficult. Patients are normally advised to:
- Remain in their doctor's surgery for at least 30 minutes after injection.
- Avoid exercising for at least three hours afterwards.
- Avoid some heart and blood pressure medications (e.g. beta blockers such as metoprolol or propranolol). It is important to talk to your doctor if starting any new medications while on AIT.
- Taking a non-sedating oral antihistamine before the injection may reduce the risk of side effects and may be recommended by your doctor.
It is important to inform your doctor about any reactions you may have experienced after your last injection and any new medications you are taking (such as eye drops, new heart/blood pressure tablets), or if you become pregnant.
Patients who are pregnant (or planning to become pregnant) are not routinely commenced on AIT until after they have given birth. If the patient is on maintenance doses of AIT and then becomes pregnant, the injections can be continued (unless the patient wishes to stop), but the supervising specialist must be contacted to discuss relevant safety issues.
Are there any potential reactions to sublingual allergen immunotherapy?
Common side effects include irritation, minor swelling or itching inside the mouth, and stomach upset/nausea. This can be controlled by temporarily reducing the dose or taking a non-sedating antihistamine beforehand. These side effects generally resolve after the first few weeks.
The risk of potentially dangerous side effects arising from this form of treatment, such as difficulty breathing, is extremely low.
Is there anything you can do to reduce the side effects from allergen immunotherapy?
Simple precautions may reduce the risk:
- Asthma should be stable before treatment starts.
- You must tell your doctor if you develop itchy eyes, itchy nose, itchy throat or chest, increased wheezing or if you feel light-headed or faint. You should never put up with these symptoms.
- Double check with your specialist and GP if you are taking any heart or blood pressure medicines or glaucoma eye drops, as some can increase the risk of side effects.
- If you are on AIT and plan to start a new heart or blood pressure medicine or glaucoma eye drop, tell your GP.
- If you have ongoing side effects, let your GP and specialist know about it as soon as possible. A few minor changes to treatment may allow you to tolerate it better.
- If you are sick or have a fever, it may be better to delay a dose. Discuss this with your GP or specialist.
Are there cases when allergen immunotherapy should not be given?
- Pregnancy: It is normally recommended not to start treatment if you are already pregnant or planning pregnancy. If you become pregnant while on treatment discuss this with your allergy specialist.
- Breast-feeding: Treatment can be started or continued whilst breastfeeding.
- Age: AIT is not normally started in children less than five years of age.
- Arm lymphoedema (swelling) after breast cancer surgery: If a lymph node dissection has been done on one arm, then do not give injections on that side. If injections can’t be given in the arm, the injections can be given elsewhere, such as the leg or under the skin of the stomach.
What are the costs of allergen immunotherapy?
- Allergen extracts for insect venoms are subsidised by the PBS in Australia and Pharmac in New Zealand.
- There is no PBS or Pharmac rebate for aeroallergens, but Specialist and GP visits attract a rebate (Medicare or Pharmac).
- Patients with private health insurance may get a rebate, but usually only for TGA registered products.
© ASCIA 2020
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Content created February 2020