Desensitising sublingual immunotherapy
What is desensitising sublingual immunotherapy (SLIT)?
SLIT is a useful treatment for severe spring or summer hay fever in patients allergic to just one type of allergen, for example grass pollen alone, or tree pollen alone. Less commonly, it can be used for allergy to two different allergens, eg. grass and birch pollen. It can also be used for desensitising patients to house dust mite or animals in individuals with very severe nasal and/or eye symptoms all year round, causing significant disability.
To qualify for treatment, patients should have failed to respond to strict avoidance of the allergen (or they may be unable to avoid it) and should already be using all recommended standard treatments, including continuous double-dose antihistamine tablets and continuous steroid nasal spray. For animal allergy, immunotherapy is usually only considered in those with occupational allergy. SLIT is not suitable for patients with severe asthma.
The objective of immunotherapy is to reduce the severity of the symptoms, improve quality of life, and reduce the dose, cost, inconvenience and any side-effects of standard treatment.
Immunotherapy for pollen-induced hay fever can prevent the later development of other allergies. For children it has the potential to prevent the development of asthma.
What does it involve?
The allergy is first confirmed by prick testing, most commonly on the forearms. Depending on the results, you may be prescribed immunotherapy and an appropriate start date will be agreed. The first treatment is taken at the hospital, with observation for one hour afterwards. Treatment may include one of the following:
Oralvac sublingual drops are prescribed on a named patient basis to desensitise the patient against house dust mites, pets, mould, grass and tree pollen. The drops are taken each morning for three years. In the case of pollen allergy, they may only need to be taken for six to eight months a year. Children over the age of five years can be treated using these drops.
Grazax Tablets are licensed tablets for grass pollen allergy and are taken six to eight months per year for three years. They are not appropriate for patients suffering from a fish allergy.
Oralair Tablets are prescribed on a named patient basis that contain five types of grass. Tablets are taken under the tongue for at least six months per year, for three years.
When will I recover?
On average patients show a 40 – 50% reduction in symptoms and additionally are able to reduce their use of medication by 30 – 40%.
The effects may be seen in the first of the three years and often last for at least two years after stopping the immunotherapy. In some patients the effects can last much longer.