HAYFEVER

What is it?

Hayfever is an allergy to pollen. Most problems occur in the summer and are caused by grass pollen.

Allergy is an abnormal reaction to often harmless substances (allergens) which are inhaled, swallowed, injected or touch the skin. Allergy causes the body to make certain defences called IgE antibodies.

Who gets it?

• Hayfever most often starts between the ages of 8 and 20. Around one in six teenagers and one in ten of the whole UK population have hayfever.
• One of the few benefits of getting older is that hayfever often becomes less severe.
• Males are a little more likely to have hayfever than females.
• Surprisingly, hayfever seems to be more common in the cities and towns than in the countryside.

Allergic conditions do run in families. A particular gene may cause people to inherit allergies from their parents. A child with one allergic parent has a 30 to 50 per cent chance of being allergic to something. If both parents are allergic the risk goes up to 60 or 70 per cent. Why some people have rhinitis, while others develop asthma or eczema is not understood yet but other genes may be important. Several types of allergic disease can occur together.

Evidence suggests that hayfever, as well as many other allergic conditions, may be getting more common. In the early 1800s doctors thought that more haymaking and a move from country to town living caused more people to develop hayfever. Nowadays many people think that pollution may be to blame.

What are the symptoms?

Hayfever is sometimes called 'seasonal allergic rhino conjunctivitis' because it affects the nose and eyes at particular times of the year. Nose symptoms include irritation and itching, sneezing, running and blockage. Eye symptoms include itching, swelling and tears. Hayfever can also make the top of the mouth (palate), throat and ears itch and cause headaches, general malaise and a loss of concentration. Pollens may also trigger asthma symptoms (cough, chest tightness and wheezing). Less commonly, contact with an allergen may cause urticaria (hives/nettle rash).

What is the treatment?

Staying away from allergens - Grass pollen is most common in mid June and in early July, although the grass pollen season may start earlier in the south-west of England and later in Scotland. Grass pollen levels are highest on hot, sunny days. Most pollen is released from the grass in the morning and rises into the air with the heat of the day, sometimes going very high. It can be blown for many miles, so cities can still have lots of pollen, especially if the wind blows over grassland. When the air cools in the evening, the 'pollen cloud' comes down and pollen counts may be very high again. On cool, wet days there is little pollen in the air.

Try to do the following:

• Avoid areas of long grass.
• Keep windows closed, especially mid-morning and late afternoon/early evening.
• Wear dark glasses.
• Keep windows shut when driving (many cars have pollen filters).
• Remember that in the UK, beaches with an on-shore breeze or mountainous areas have less pollen.
• Check the climate of a country before you plan your holiday.
• Check the day's pollen forecast if you are planning an outing. Pollen counts (the average number of pollen grains in each cubic metre of air) are made at numerous sites throughout the country, and the counts and forecasts published through the media. Sometimes a 'laminar flow helmet', which filters the air a person breathes, may be useful for severely affected farm workers. They are also used for other 'occupational' allergies.

Medicines - Today's medicines can control most hayfever symptoms. Several different ones may be used and they must be taken according to the recommended dose:

Antihistamines - These are widely used to stop many of the effects of histamine which is released during allergic reactions, Modern antihistamines such as acrivastine (Semprex), astemizole (Hismanal), cetrizine (Zirtek), loratadine (Clarityn) and terfenadine (Triludan) cause little, if any, sleepiness. They help both eye and nose symptoms, although they are less helpful for a blocked nose than for sneezing and running noses. The few side-effects from these modern antihistamines may include headaches, dry mouth, skin rashes and upset bowels. In many individuals the older antihistamines do not cause sleepiness. A new antihistamine called azelastine (Rhinolast) is available as a nasal spray.

Decongestant sprays - These may be used to unblock the nose but these should only be used in the short term.

Anti-inflammatory - Anti-inflammatory nose and eye medicines, if used regularly, are very helpful for many people with hayfever. There are two main types: sodium cromoglycate and corticosteroids. Although they work in different ways, both have good anti-allergic effects. They cut down both the number of inflammatory chemicals and the number of inflammatory cells in the nose and eye. They also prevent symptoms when used regularly and ideally should be started before the hayfever season.

Sodium cromoglycate - This is used both for the nose (Rynacrom) and for the eye (Opticrom), where it is very effective. Side-effects may include some nose or eye irritation. Lodoxamide (Alomide) is a new anti-allergic eye drop.

Corticosteroid nose medicines - These also control symptoms very well. They can be used as liquid sprays (Beconase Aqueous, Flixonase, Syntaris); or as aerosols (Beconase, Rhinocort); or as nose drops (Betnesol, Vista-Methasone). Side-effects may include some irritation and sometimes nose bleeds. The amount of corticosteroids in these medicines is small. They do not generally cause serious side-effects unless the recommended dose is exceeded.

Because nose drops and sprays only work if the medicine gets into the nose, if your nose is blocked you may need a decongestant for a few days. If not, you may need to tip your head upside down for a few minutes so that the drops stay in the nose. Often the best way to control symptoms is to take sprays and drops for the nose and eyes, together with an antihistamine tablet. If these medicines fail, treatment with corticosteroid tablets may be given. A long-acting injection is an alternative but more commonly causes side-effects. People who wheeze with their hayfever have asthma and should ask their doctor for treatment. For more information about asthma please see our 'Take control of asthma booklet'.

Making the body less sensitive (immunotherapy) - The use of injections that make the body less sensitive was greatly cut down in 1986. The treatment is only available in specialist hospital units because it can cause serious side-effects, particularly in patients with asthma. Safer and more effective vaccines are being looked at and it is likely that this popular form of treatment will be more widely available in the future.