Allergic rhinitis
What is allergic rhinitis?
Allergic rhinitis is inflammation of the nose resulting from an allergy. It affects five to 10 per cent of the population. A very common form is hay fever.
What causes allergic rhinitis and what are the risk factors?
An allergy is a response by the body's defence system (the immune system) to something that is not a harmful infection. Such 'harmless' substances (allergens) include pollen, cat hair, animal dander, the house dust mite and mould spores.
It is not known why people develop allergic rhinitis. It is more common in people from families with eczema and asthma and there is probably an inherited factor that affects the way the immune system reacts to allergens.
What are the symptoms and complications of allergic rhinitis?
Allergic rhinitis results in a runny, itchy and blocked nose. On lying down at night the fluid in the nose drips down on to the back of the throat and causes bouts of coughing, which can be uncomfortable and disturb sleep.
How do doctors recognise allergic rhinitis?
Allergic rhinitis is usually diagnosed on the basis of the symptoms and their seasonal nature if it is hay fever or their association with a particular allergen such as cat hair.
Year-round allergic rhinitis due to mould spores or house dust mite is more difficult to diagnose as there are other similar forms of rhinitis that do not result from allergy. More than one allergen may be involved
What is the treatment for allergic rhinitis?
Self-care action plan
A self-care action plan to avoid the allergen and so minimise the symptoms of allergic rhinitis includes:
- Keeping windows closed and using an air ioniser (for pollen)
- Regular vacuuming using a vacuum cleaner with a pollen filter (all allergens)
- Damp dusting, so preventing dust from being dispersed into the air (for house dust mite)
- Use of special bed and pillow coverings and regular laundering of bedclothes
Medicines
A variety of medicines can be bought at the chemist to treat allergic rhinitis. Probably the most effective is a beclomethasone nasal spray. This acts to stop the inflammation in the nose, but takes a few days to produce this effect and so needs to be started before the symptoms become too severe. Once the symptoms are severe it may be sneezed straight out again. Another nasal spray that can be used is sodium cromoglycate. This is less effective than beclomethasone but is often the first choice of treatment in children as prolonged use of beclomethasone can occasionally affect the growth of children.
Other popular medicines are antihistamines. These also act to reduce the inflammation, but unlike the beclomethasone nasal spray they have an immediate effect. However, most need to be taken as a tablet, which means that they have effects on other parts of the body as well. There are a couple that can be taken as a nasal spray but they do not appear to be as effective as the beclomethasone nasal spray.
Older types of antihistamine can cause drowsiness and this means that people taking them should not drive. Newer antihistamines do not cause drowsiness but they can have other effects and some of these might not yet have become evident as they are so new. One in particular called terfenadine has recently been banned in the USA and is only available in this country now with strong warnings to avoid taking it with certain other medicines, including a fairly commonly prescribed antibiotic called erythromycin, and also grapefruit juice, because these combinations can cause a life-threatening type of palpitation. Astemizole is another antihistamine that can cause a life-threatening type of palpitation when used with other medicines.
Although allergic rhinitis is common in young women, none of these medications is recommended for use during pregnancy. All should be avoided if possible during pregnancy and increased efforts should be made to minimise exposure to the allergen as outlined in the self-care section of this factsheet. If the symptoms remain a problem, a doctor should be consulted.
Hyposensitisation
This involves giving gradually increasing doses of the substance that causes the allergy and in the process making the immune system less responsive to it. This should only be carried out under close medical supervision as occasionally this treatment causes a life-threatening allergic response that must be treated immediately with an injection of adrenaline.
Complementary therapy
Some complementary therapies (homoeopathy, osteopathy and acupuncture) claim to have beneficial effects on hay fever, but the explanations for their effect are not consistent with the traditional medical understanding of hay fever. Shiatsu, the Alexander technique and aromatherapy may help to improve general well-being and symptoms.
What is the outcome of allergic rhinitis?
Allergic rhinitis tends to improve with increasing age, possibly because the immune system becomes less responsive with age.
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