Immunotherapy is a type of treatment for allergies that works by suppressing a specific immune response. It is a way of changing the body’s immune system to help it to recognise harmless substances and learn not to respond negatively to them. This is known more specifically as suppression immunotherapy, and is the only available treatment for allergies that deals with the allergy itself rather than treating the symptoms, such as antihistamine or steroids.
Immunotherapy works by exposing the body to the allergen a miniscule amount at a time, allowing the body to slowly adjust and become less sensitive to it. This process is known as desensitisation. The treatment is administered by a course of injections, tablets or drops under the tongue over a period of one to three years by a doctor or allergist and is normally only used in very serious cases, especially if the patient is at risk of anaphylactic shock, or if they find it hard to live a normal life due to their allergies. It is not usually recommended for food allergies, although recently clinical trials have begun to try and develop immunotherapy for food allergies.
Another method of immunotherapy for allergies is known as ‘rush’ immunotherapy. This is normally delivered in hospital, as it involves a more rapid administration of the allergen over a shorter period of time. This is often appropriate for bee or wasp sting allergies, as speeding up the process means that the patient will be safer from another sting more quickly. This method can be just as effective as the slower method but due to the associated risks, care must be taken.
Patients considered for immunotherapy are normally those whose allergies are life-threatening. Immunotherapy does not work for everyone, and in some people will only improve symptoms rather than cure the allergy completely. It is most effective when started as early as possible, in children or as soon as the allergy has been diagnosed.