ALLERGY

Some people become ill when they come into contact with a substance which may have no effect on other people. This is known as an allergic reaction - the person has an allergy to the substance. An allergic reaction can show itself in different ways, such as sneezing, an itching or runny nose, breathing problems, and coughing.

The substance which causes such a reaction is known as an allergen. Common examples of allergens which affect the lungs include pollens from grass and trees, house dust mite, and animal fur. Between a quarter and a third of the population are more likely than others to have allergies. This tendency runs in families. However, not all the people who have this tendency actually get allergy problems.

Common allergies

Some allergies can cause problems all through the year, while others only affect at certain times. The most common cause of year-round allergy is the house dust mite. These tiny mites, found in every home, feed off human skin scales which are shed naturally. House dust mites are especially common in bedding, such as pillows and mattresses. Another common cause of year-round allergy is skin and fur from cats and dogs, horses, and other animals.

Some people suffer from allergy because of substances at their place of work, such as certain kinds of dust. Allergens which cause problems only at certain times of the year include pollen from trees (springtime), from grass (high summer), or weeds (late summer). Some plants produce mould spores which may cause allergy in late summer and autumn.

Effects

By far the most common allergic illness in the United Kingdom is summer hayfever from grass pollen. Hayfever usually causes itching, sneezing, and a runny or blocked nose. Other problems can include sore eyes, an itchy palate (the roof of the mouth) and breathing problems.

Hayfever can be an embarrassing problem because of the constant need for nose-blowing which spoils what, for most people, is the best time of year. Itching and sneezing can also make it difficult to work or study properly. Most hayfever sufferers find that they feel much better if they regularly use hayfever treatments, such as nose sprays and tablets. Consult a local GP or pharmacist for advice on suitable treatment.

Allergy can often cause asthma, a common lung disease which can make breathing difficult, and gives a tight feeling in the chest. Asthma affects people of any age, although it is most often found in the young and middle-aged. Asthma may be set off by a year-round allergen such as house dust mites, or by a seasonal one, such as pollen.

Asthma caused by substances breathed in at work can be serious and long-lasting. Some people find that they still have asthma even after they leave work or the substance is removed. It is important to find out what is causing the problem, and to avoid that substance if possible.

Allergens which can cause lung problems are more common in some jobs than others. Farmers who work with mouldy hay may be prone to "farmer's lung". People who handle birds (including people who keep pigeons, budgerigars, or other birds as a hobby) may get a form of allergy which affects the air sacs in the lungs.

Most people who do these jobs are not likely to have problems. Up to a third of people have a family tendency to get allergies, and some of these people may react to the allergens. However, although problems such as "pigeon-fancier's lung" are rare, they may cause lung damage which will get worse the cause is found and then avoided.

Diagnosis

Some allergies are easier to diagnose than others. For example, hayfever or asthma which gets worse in June and July is very likely to be due to an allergy to grass pollen. With other allergies, such as house dust mite or animal fur, special tests may be required to determine the problem. A GP may refer a sufferer of a lung allergy to a lung specialist.

Avoiding allergens

It is difficult to avoid pollens, the most common cause of allergic illness. It may help to wear sunglasses, and to keep windows shut, especially when in cars and tall buildings. Avoid open grassy spaces, particularly during the evening or at night, when there is more pollen at ground level. A holiday by the sea, or abroad, during the peak pollen season may help. If a bad allergic problem is caused by cats or dogs, then it is better not to keep such pets.

If this is not possible, then keep the animal out of doors as much as possible, and keep the house very clean. Washing a cat or dog once a week is also an effective way of reducing allergen levels in the home. To reduce house mite problems, use special covers for mattresses, pillows and duvets. Clean the house often, as carefully as possible, and allow plenty of air in - this helps to reduce the dampness that house dust mites like. It helps to use a good vacuum cleaner, fitted with a small pore-size filter.