LOW-DOSE EXPOSURE COULD BE A ‘CURE’

PATIENTS with severe allergy may be able to undergo treatment called desensitisation, also known as allergen immunotherapy.

This ‘modifies’ the immune system so the body has a reduced reaction (or no longer reacts) when in contact with the allergen; symptoms become progressively less severe, and in some cases disappear altogether. It’s very effective for allergies to pollen and house dust mites, and bee and wasp stings.

WHAT IT INVOLVES: Initially tiny quantities of allergen are introduced to the patient, followed by gradually increasing concentrations to allow them to build up a tolerance. The treatment starts with injections every week, and then every four to six weeks, for three years.

In some cases, the allergen can be given via drops or tablets under the tongue on a daily basis for the same period. It usually takes at least six months before symptoms improve, often longer. However, after completing the course, many people stay symptom-free, or have reduced symptoms, for a number of years.

A 2007 Cochrane review of 51 studies involving 2,871 patients with hay fever who underwent allergen immunotherapy found it resulted in ‘significant reductions in symptom scores and medication use’.

WHO CAN GET IT: In this country the treatment is generally reserved for severe allergies to bee and wasp stings, and severe hay fever, that have not responded successfully to medication. There can be a long wait for treatment because NHS allergy services are often under-resourced and overstretched — some areas don’t even have an allergy specialist. Immunotherapy for food allergies is new and only available as part of research at specialist centres.