Reviewed by Professor Brian Lipworth, professor of allergies and respiratory medicine
What is hay fever?
Hay fever, otherwise known as seasonal allergic rhinitis, is an allergic reaction to airborne substances such as pollen that get into the upper respiratory passages - the nose, sinus, throat - and also the eyes.
Perennial allergic rhinitis is a similar allergy that occurs all year round and is caused by things such as house dust mites and pets. However the predominant allergen changes from time to time.
Why do you get hay fever?
Histamine irritates the upper respiratory passages, making them swell and producing the typical hay fever symptoms.
A tendency to suffer allergies is often hereditary. The most common causes of hay fever are:
Often it will be enough to tell the doctor when, where, and how your symptoms occur. Skin tests and specific blood tests can be used to confirm what exactly you are allergic to.
Hay fever sufferers are more vulnerable to other allergic respiratory diseases, eg asthma, and sleeping difficulties that can lead to chronic fatigue (because of blocked nasal passages and snoring).
If you suffer from hay fever you should do whatever you can to avoid substances that provoke hypersensitivity. Otherwise you will increase the risk of developing other, more serious, allergic diseases.
Symptoms can be controlled through treatment, but you can't get rid of the allergy itself. However, hay fever is usually more of a nuisance than a harm to health, and the symptoms of many people improve over time.
What medicine can I take?
There are numerous medicines that can be used to relieve the symptoms of hay fever. Many of these are now available over-the-counter from pharmacies and your pharmacist will be able to advise on which are most suitable for you.
The choice will often depend on which symptoms trouble you the most.
Antihistamine tablets and syrups
Antihistamines prevent the histamine your body produces to the allergen from causing the allergic symptoms.
They are good at relieving sneezing, itching and runny nose and eye symptoms, but are slightly less effective at reducing a blocked nose.
There are two main types:
Many people prefer to use the newer medicines because they can usually be taken once daily and allow you to get on with your daily activities without problems.
Many antihistamines can be bought over-the-counter, but some, eg fexofenadine (Telfast), are available on prescription only.
Antihistamine nasal sprays
An antihistamine that is used directly in the nose is azelastine (Rhinolast nasal spray). It is only available on prescription.
This can be used to provide rapid relief of sneezing, itching and runny nose, but has no effect on other symptoms such as itchy eyes.
It can also be used regularly to prevent nasal symptoms, but is less effective than nasal corticosteroids.
There are two nasal corticosteroid medicines that can be bought from pharmacies: beclometasone (eg Beconase hayfever nasal spray) and fluticasone (eg Flixonase allergy nasal spray). Others are also available on prescription only.
Nasal steroids reduce inflammation in the nasal passages and are better than oral antihistamines at relieving most nasal symptoms, including a blocked nose. They also relieve eye symptoms.
Nasal steroids have to be used regularly to be effective. They are best started a couple of weeks before the pollen season begins.
Nasal sprays containing sodium cromoglicate (eg Rynacrom nasal spray) are also used to prevent nasal symptoms, ideally starting treatment a couple of weeks before the pollen season.
They are less effective than nasal corticosteroids, but are often the first choice for young children.
Nose drops and sprays containing decongestants such as xylometazoline (eg Otrivine nasal spray, Sudafed decongestant nasal spray) can be bought over-the-counter to treat a blocked nose.
They should only be used for a few days, otherwise they can cause ‘rebound congestion’ when you stop using them.
Antihistamine eye drops
Antihistamine eye drops can be useful if eye symptoms are your biggest problem. They include antazoline (Otrivine antistin), which you can buy from pharmacies, and azelastine (Optilast), epinastine (Relestat), ketotifen (Zaditen) and olopatadine (Opatanol), which must be prescribed by your doctor.
The drops provide rapid relief from itchy, red, watery eyes.
Cromoglicate eye drops
Drops containing sodium cromoglicate (eg Clarityn allergy eye drops, Optrex allergy eye drops) or nedocromil sodium (Rapitil eye drops) should be used regularly, as with nasal cromoglicate products, to prevent the allergic reaction occurring.
Cromoglicate drops can be bought from pharmacies and are also suitable if eye symptoms prevail.
Immunotherapy (desensitising vaccines)
This treatment is only used when allergen avoidance and medicines have proved ineffective at treating a severe allergy.
Injections of small amounts of the known allergy-causing substance are given to create tolerance to the allergen and prevent the immune system producing too much histamine when it encounters it.
This treatment has to take place over a long time and requires strict adherence.
|Based on a text by Dr Flemming Andersen
|Last updated 01.08.2005
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