Hay fever symptoms during the spring and summer can of course be miserable and get in the way of your normal activities over a period of many months. If this has been the case for you in previous years, and particularly if antihistamines and nasal sprays are not giving you the relief you need, it may be time to consider allergen desensitisation or immunotherapy as it is often called.
Immunotherapy has a long pedigree going back over 100 years, traditionally, the treatment has required injections given into the upper arm at regular intervals in order to desensitise the immune system to the allergen causing symptoms.
These injections contain a highly purified and standardised extract of that allergen and the dose is gradually increased until a degree of tolerance is induced.
Over the last 5-10 years, a new form of immunotherapy has gained popularity. In contrast to injections, the new approach involves taking immunotherapy under the tongue, either as a dissolvable tablet or liquid. A major advantage of this approach is that the likelihood of a significant allergic reaction to the allergen, a not uncommon side effect of injection immunotherapy, is much less than with the injection form of treatment. Plus, after the first dose is taken with your allergist, the treatment can then be taken at home making this an easy medication to administer and minimizes costs.
The GRAZAX grass pollen immunotherapy tablet is effective as evidenced by large clinical trials and is now licensed by regulatory bodies in the European Union and North America. Treatment should be taken daily and started several months before the onset of the grass pollen season.
Typically in the UK, this means starting by February/March – meaning it’s important to start thinking about immunotherapy even in winter.
Sublingual immunotherapy is also available for other allergens including tree pollens, house dust mite, cat and dog allergies. Although these treatments are not licensed by the regulatory authorities in the UK, for the right patients these can still be obtained and prescribed by an Allergy Specialist if a clinical need is established. Here in the UK, the most troublesome tree pollen is generally that from birch, with symptoms in March and April. Sublingual immunotherapy with birch pollen is started around December time – so if you suffer with birch allergy you should start thinking about immunotherapy now.
Unlike antihistamines and nasal sprays, immunotherapy fundamentally alters the way in which the immune system responds to allergens. Since the immune system has memory, this can mean that clinical improvement may be sustained even after treatment is finished. For example, clinical trials of GRAZAX have shown that improvement in hayfever symptoms over 3 years of treatment can be sustained for a number of years after the course is finished. More recently a clinical trial in children with hayfever due to grass pollen showed that GRAZAX treatment was associated with a lower rate of progression from hayfever to asthma symptoms.
It is widely considered that sublingual immunotherapy is safer and better tolerated than the conventional injection treatment. It is quite normal for sublingual vaccines to cause some itching under the tongue, even some mild swelling. Typically, this resolves after a week or two of treatment. Less common symptoms include dyspepsia and in rare cases a more vigorous allergic reaction, hence the need for medical supervision of the first dose.