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| Hay fever and perennial allergic rhinitis |
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Reviewed by Professor Brian Lipworth, professor of allergies and respiratory medicine
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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.
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What's in a name?
The name hay fever is misleading because symptoms don't just
occur in autumn when hay is gathered and never include fever.
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Hay fever is the most common of all the allergic diseases -
about 15 per cent of the population in industrialised countries suffer from
this condition. Symptoms usually appear in childhood first and then lessen by
the age of 30 or 40.
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?
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| Frequent sneezing is characteristic of hay fever. |
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Different microscopic substances get into the nose and cause the
body to produce antibodies and release histamine.
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:
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tree pollen such as elder, elm, hazel and especially birch
(spring hay fever).
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grass pollen (summer hay fever).
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mugwort and hybrids such as chrysanthemum (autumn hay fever).
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house dust mites and
mould fungus - particularly associated with perennial allergic
rhinitis.
What are the symptoms of hay fever?
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Itchy and watery eyes.
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Frequent sneezing, a bunged up or runny nose.
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Itching on the roof of the mouth.
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Coughing.
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Wheezing or a burning sensation in the throat.
What can cause hay fever?
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The pollen to which you are allergic.
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Genetic predisposition associated with other atopic diseases,
eg
eczema or
asthma.
How does the doctor make the diagnosis?
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.
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Good advice
If your hay fever is caused by various pollens, try to keep
doors and windows shut during the pollen season.
Let someone else mow the lawn.
Check pollen forecasts. Try to avoid outdoor activities if very
high.
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In the long term
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:
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those that cause drowsiness, such as chlorphenamine (eg Piriton)
and
promethazine (eg Phenergan)
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newer medicines that cause less or no drowsiness, such as
acrivastine (eg Benadryl allergy relief), cetirizine (eg Zirtek allergy) and loratadine (eg Clarityn allergy).
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 and drops
Antihistamines that are used directly in the nose are
azelastine (eg Aller-eze nasal spray) and
levocabastine (eg Livostin direct nasal spray), both of which can be
bought over-the-counter.
These can be used to provide rapid relief of sneezing, itching
and runny nose, but have no effect on other symptoms such as itchy
eyes.
They can also be used regularly to prevent nasal symptoms, but
are less effective than nasal corticosteroids.
Nasal corticosteroids
There are two steroid nasal preparations 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 cromoglicate
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.
Nasal decongestants
Nose drops and sprays containing decongestants such as
xylometazoline (eg Otrivine nasal spray, Sudafed 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, azelastine (eg Aller-eze eye drops)
and levocabastine (eg Livostin direct eye drops), which
you can buy from pharmacies.
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.
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Based on a text by Dr Flemming Andersen
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Last updated 01.08.2005
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