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Allergies > Doctors: Immunotherapy

Immunotherapy

Immunotherapy may be able to:

- provide a permanent cure for allergic rhinitis (rather than treating the symptoms)
- prevent the development of new allergies, particularly in children

It is generally given as an injection, but treatments given under the tongue and in the nose are being developed.

How does Immunotherapy work?

Allergic rhinitis is caused by an immune response to a foreign body (allergen).

Immunotherapy causes complex changes to the body’s immune system that prevents or reduces this immune response.

For example, allergens are recognised by your body by components of the immune system called antibodies. These start the body’s immune response against the allergen. In people with seasonal allergic rhinitis, the level of antibodies in the nose rises during the pollen season, and returns to normal when the season ends. Allergen immunotherapy can reduce this seasonal rise in antibodies

During immunotherapy, you receive small doses of the allergen that induces your allergic rhinitis. As a result, you become desensitised to this allergen. This means that when you encounter the allergen naturally, your allergic response is reduced.

Research suggests that using immunotherapy against one allergen may prevent people developing other allergies. This might be particularly useful in children, as allergies tend to develop early in life. Recent studies have indicated that immunotherapy may prevent the development of asthma in children with allergic rhinitis.

How do i take Immunotherapy?

Immunotherapy is usually taken via injections that are given by a trained professional.
Typically, for the first few months you are given weekly injections of increasing doses of allergen. When you have reached the maximum dose, you will then receive this dose once every 1–2 months, usually for 3–5 years. Immunotherapy becomes effective after a few months, and the benefits may last for several years after treatment has been stopped.

Is Immunotherapy Safe?

When immunotherapy is given by injection, there is a small risk that you might have an immune reaction to the allergen that is being injected into the blood stream. This reaction can range from mild to fatal. The risk of such a reaction (of any severity) has been calculated as 0.1–1% per injection, or about 5% per patient per year.

Asthma appears to be a risk factor for such a reaction. In the UK, people with asthma are advised not to have immunotherapy. However, in many other countries, including the US, asthma patients can be treated with immunotherapy.

Immunotherapy that can be taken under the tongue or in the nose is in development. This is not thought to produce life-threatening reactions

Who should have Immunotherapy?

Immunotherapy is suitable for people who are allergic to only one or two allergens.
Your doctor may suggest it to you if other medications do not help your symptoms, or if you get side effects from these treatments.

Immunotherapy does not involve any drugs, only small doses of the allergen that you are allergic to. It therefore may be suitable for people who would prefer not to use drugs.

Immunotherapy involves repeated injections for many years, and carries the small risk of a life-threatening immune reaction following an injection.

If you and your doctor think that you may benefit from immunotherapy, you will need to be referred to an allergy specialist

References

Li JT. Immunotherapy for allergic rhinitis. Immunol Allergy Clin North Am 2000;20:383–400.

Bousquet J, Lockey R, Malling HJ, WHO panel members. Allergen immunotherapy: therapeutic vaccines for allergic diseases. A WHO position paper. J Allergy Clin Immunol 1998;102:558–562.

van Cauwenberge P, Bachert C, Passalacqua G, et al. Consensus statement on the treatment of allergic rhinitis. European Academy of Allergology and Clinical Immunology. Allergy 2000;55:116–134.