Surveys in general practice suggest around 40% of patients with hay fever don’t respond to the antihistamines and nasal sprays, says Professor Durham. One of the problems is that lots of us simply don’t take the medication, or not all the time.
In those known to be taking the right drugs the right way, Professor Stephen Durham estimates that only one in ten people with allergic rhinitis don’t respond. ‘They’re the people offered immunotherapy and of those 80% respond. Not just for grass pollen but also for dust mites, trees and ragweed. The good news is immunotherapy also works well in older patients as well.’
Immunotherapy requires referral to an NHS allergy clinic and identification of the allergen, usually by skin prick tests, then a gradual exposure to increasing doses of the allergen, initially in tiny doses but then in increasing amounts. This is either by an injection under the skin once a week followed by monthly injections for seven months pre and post season, thereafter continuing monthly injections usually for three years (subcutaneous immunotherapy or SCIT). Nowadays immunotherapy can also be given in the form of grass pollen extract as drops or tablets under the tongue (sublingual immunotherapy or SLIT).
Sublingual immunotherapy should be prescribed by a specialist but can be self-administered daily by patients whereas the injections require visits to the allergy clinic in view of the small risk of developing an allergic reaction.
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The good news is that Professor Durham’s research at Imperial College London and Royal Brompton Hospital has shown that the treatment works within three to four months so you get protection in the first year but, more importantly, three years of continuous treatment gives a minimum of two years protection after stopping treatment and induces acquisition of long term tolerance.
The drawback of immunotherapy is the cost and length of time required to administer and much of Professor Durham’s research work as a member of the steering committee of the Immune Tolerance Network in the US (ITN) is looking at quicker and easier methods.
Your GP can refer you to an NHS allergy clinic but be prepared for a wait. Lynne Regent, a member of The National Allergy Strategy Group, NASG, and Chief Executive of the Anaphylaxis Campaign, says while some of the best and highest profile research is focussed in the UK we do not have enough allergy clinics: ‘We have fantastic clinicians and researchers but too few NHS clinics and what provision there is tends to be in the south east and around big conurbations. Awareness and training in GPs could be much better and more time needs to be allocated as part of doctors’ training. Bearing in mind the increasing prevalence of allergy this needs to be rectified.’
Future treatments for autoimmune conditions?
Autoimmune diseases occur when the immune system produces antibodies that mistakenly attack healthy tissue and the hope is that discovering the antigens that prompt this response may make it possible to treat some of these diseases by specific immunotherapy as is the case for specific allergies. For example, in the case of multiple sclerosis, a protein in the myelin sheaf surrounding the nerves has been found to be one of the antigens. Studies are still at an early stage but researchers at King’s College London have identified two antigens involved in Type 1 Diabetes.