Hay fever

Hay fever, also known as seasonal allergic rhinitis, is a very common condition that affects 20% of people in the UK. It is caused by an allergy to airborne substances such as grass or hay pollens, which affects the upper respiratory passages (nose, sinus, throat and eyes).

Hay fever usually occurs during the spring and summer months. Exactly when you get it depends on which pollens you are allergic to. From May to July grass and flowers are in pollen, making these the most common cause of hay fever. During spring, from March to May, pollens from trees are the most common cause of hay fever. Some people do get hay fever into the autumn months. However this is rare and is usually caused by weeds such as nettles and docks, late flowering plants, and mould spores.

Hay fever symptoms can be similar to a cold, and include a runny nose, watery eyes and repeated sneezing attacks. As with all allergies, the symptoms happen as a result of your immune system (the body's defence system) overreacting to a normally harmless substance in this case, pollen. When the body comes into contact with pollen, cells in the lining of your nose, mouth and eyes release a chemical called histamine that triggers the symptoms of an allergic reaction.

You are more likely to get hay fever if there is a history of allergies in your family, particularly asthma or eczema. Hay fever usually begins in the early teens and peaks when you're in your twenties. Research shows that many people become less sensitive to pollen as they get older, and by the time they reach their mid-forties, hay fever may no longer be a problem.

Hay fever symptoms vary in severity and you may find that your symptoms are worse some years than others, depending on the weather conditions and pollen count. Your symptoms may also start at different times of year depending on which type of pollen you are allergic to.

In general, the symptoms of hay fever are:

• frequent sneezing,
• runny or blocked nose,
• itchy or watery eyes, and
• an itchy throat, mouth, nose and ears.

Less commonly, you may experience:

• loss of smell,
• face pain (caused by blocked sinuses),
• sweats, and
• headaches.

If you have asthma, you may find that your symptoms, such as wheezing and breathlessness, get worse when you have hay fever as well. Sometimes, asthma symptoms only occur during the hay fever season.

Pollen count

Hay fever symptoms are likely to be worse if the pollen count is high. The pollen count is the number of pollen grains found in each cubic metre of air. This is not determined simply by how many flowers there are, but also by the weather. The amount of sunshine, rain or wind there is affects how much pollen plants release. Hay fever symptoms tend to begin when the pollen count is over 50.

During the pollen season, plants release pollen early in the morning. On a sunny day, as the day gets warmer and more flowers open, pollen levels may rise, and the pollen is carried high up into the air. The pollen count is therefore highest in the early evening, so if you have hay fever, it is a good idea to avoid going outdoors at this time.

On humid and windy days, pollen spreads easily. On rainy days, pollen may be cleared from the air causing levels to fall.

Hay fever is an allergic reaction to pollen. When pollen comes into contact with the cells that line your mouth, nose, eyes and throat, it irritates them. If you are allergic to pollen, your body thinks it is harmful, and produces a special type of antibody, known as Immunoglobulin E (IgE), to attack the pollen. This triggers the release of further chemicals, including histamine, which together cause the symptoms of an allergic reaction.

In England, most people with hay fever are allergic to grass pollen. However, trees, mould spores and weeds can also cause hay fever. Research also shows that pollution, such as cigarette smoke or car exhaust fumes, can also make allergies such as hay fever worse.

You should see your GP if you think you have hay fever. Your GP will usually be able to make a diagnosis from a description of your symptoms, especially if you can tell them what times of the day or year your symptoms occur.

Hay fever is normally obvious from the symptoms, but in a few cases a skin or blood test may be used to work out exactly what you are allergic to. This may be done if you have hay fever symptoms all year round (perennial allergic rhinitis), which could be caused by other substances as well as pollen, such as house-dust mites, animals, chemicals or some foods.

A skin test is usually done first because it is quick and straightforward. The skin is pricked with a tiny amount of the substance that you are thought to be allergic to and the amount of IgE antibodies, made by the body to counteract it, is measured.

A blood test involves taking a small sample of blood to measure the amount of the IgE antibody present.

As with most allergies, the best way to control them is by avoiding the trigger substance. However, it would be very difficult to avoid pollen, particularly during the summer months when you want to spend more time outdoors.

Fortunately, there is a range of products available to treat the symptoms of hay fever. For them to be most effective, you should try to minimise your exposure to pollen, by avoiding tasks such as mowing the lawn, and by staying indoors when the pollen count is high (between 50-150).

The types of hay fever treatment available include; tablets, nasal sprays, eye drops and creams:

• Antihistamine tablets or nasal sprays these stop histamine, the chemical released by your body, from causing the symptoms of an allergic reaction. There are two types of antihistamine - those that cause drowsiness and those that do not. Antihistamines are usually effective at treating itching, sneezing and watery eyes, but antihistamine nasal sprays may not help if your nose is blocked. Many antihistamines are available over-the-counter at your pharmacy, and most can be used daily or often.
• Steroid nasal sprays and drops these are more effective than antihistamine tablets in preventing and relieving nasal (nose) symptoms, including sneezing and congestion. They can also relieve itchy, watery eyes. They are most effective if you start using them a couple of weeks before your symptoms usually begin, and work best when used regularly. Many are available over-the-counter but you may need a prescription for some.
• Eye drops these work by reducing the release of histamine from your eyes, which eases itching and swelling. Eye drops containing the active ingredient cromoglycate are most widely used, and are normally used alongside other treatments, such as antihistamine tablets and steroid nasal sprays.
• A cream that blocks pollen has been developed and research is currently being undertaken to see how effective it is in reducing the symptoms of hay fever and other allergies.

If you have severe, long-term hay fever, immunotherapy or desensitisation treatment may be an option. You are gradually introduced to small amounts of the substance that you are allergic to, such as pollen, to monitor the allergic reaction. This treatment is only carried out in specialist medical centres, in case a serious allergic reaction occurs.

Some complementary therapies, such as acupuncture, homeopathy and herbal medicine, may claim to relieve or prevent hay fever symptoms. However, the lack of evidence supporting their effectiveness means that more research is needed before they can be recommended.

To decide what the most appropriate treatment is for you speak to your GP. This is particularly important if you have asthma as well, because hay fever can often make asthma symptoms worse. If it does, it may mean increasing the dosage of your asthma medication.

It is very difficult to completely avoid pollen, but you should be able to ease the severity of your hay fever symptoms by taking some sensible precautions. Reduce your exposure to pollen by trying to stay indoors when pollen counts are high.

The pollen count is often given with TV, radio, internet, or newspaper weather forecasts. If it is humid or windy, the pollen count is likely to be higher. Generally, the pollen count is highest in the early evening, so try to avoid going outside around this time. You can also try the following:

• keep windows and doors shut in the house if it gets too warm, try drawing the curtains to keep out the sun and keep the temperature down,
• avoid cutting grass, playing or walking in grassy areas, and camping,
• change your clothes and take a shower after being outdoors to remove the pollen on your body,
• wear wrap-around sunglasses to stop pollen getting in your eyes when you are outdoors,
• keep car windows closed, and consider buying a pollen filter for the air vents in your car,
• keep fresh flowers out of the house, and vacuum (ideally using a machine with a HEPA filter) and damp dust regularly,
• do not smoke and stop other people from smoking in your house smoking, and breathing in other people's smoke, irritates the lining of your nose, eyes, throat and airways which can make your symptoms worse, and
• keep pets out of the house during the hay fever season if your pet does come indoors, wash it regularly to remove any pollen from its fur.