Allergic asthma Dr Adrian Morris Asthma affects the small airways that carry air in and out of the lungs. These airways can become inflamed, swollen and contract. You may be one of the more than 5.2 million people in the UK who have asthma.

In this article

What causes it? What are the symptoms?

What's the treatment? Can I prevent asthma?

Asthma often runs in 'atopic' families. Children are also more likely to develop asthma if their mother smoked during pregnancy or while breastfeeding.

Most people find several things trigger their asthma. Some of the most common predisposing factors for asthma are allergies to:

• House dust mites
• Mould spores
• Pollen
• Pets
• Food or food preservatives

Asthma triggers include:

• Viral infections, such as colds and flu
• Cigarette smoke
• Certain forms of exercise, such as running
• Exposure to cold, dry air
• Laughing and other emotions
• Medication containing aspirin
• Drinks containing sulphur dioxide, such as squashes and lemon barley water

The main symptoms are coughing, wheezing, shortness of breath and a tight feeling in the chest.

There are two main treatments for asthma:

• Relievers - salbutamol and terbutaline
• Preventers - beclomethasone, budesonide, fluticasone, mometasone and ciclesonide

These all come in a variety of delivery devices, such as aerosol or powder inhalers and nebulisers. You breathe the medicine in through your mouth, directly into your lungs.

Relievers are drugs called bronchodilators (based on adrenaline) that relax the muscles which surround the airways, making it easier to breathe. You should take these as directed by your doctor as soon as symptoms appear.

Taking a dose of the reliever inhaler before exercise will increase your stamina and prevent breathing difficulty.

Preventers are drugs (usually low-dose steroids) that reduce inflammation in the airways and make them less sensitive. This means you're less likely to react when exposed to a trigger.

The protective effect of this medicine is built up over a period of time, so you must take your preventer regularly

The protective effect of this medicine is built up over a period of time, so you must take your preventer regularly, as directed by your doctor.

Combination preventer and long-acting reliever (formoterol and salmeterol) inhalers have become popular and seem to be particularly good at controlling more severe and persistent asthma.

If your asthma is really bad, your doctor may also prescribe a short course of steroid tablets to calm your inflamed airways.

Newer anti-inflammatory medication includes leukotriene receptor antagonists (montelukast and zafirlukast), which are particularly useful for brittle asthma and patients with aspirin-sensitive asthma.

The most recent addition to the list of possible treatments for asthma is a new injection medication (omalizumab) for those with severe allergic asthma, which works by dampening down the IgE allergic reaction.

An older orally administered bronchodilator, theophylline, isn't often used these days owing to its unpredictable toxic side-effects and need for blood testing.

There is little scientific evidence to support the use of breathing exercises, such as Buteyko, in the treatment of asthma. However, some people with asthma find breathing exercises calm their symptoms and reduce their need for reliever medication.

You can help to avoid asthma attacks by taking preventer medicine regularly and avoiding your triggers. You can also monitor your asthma by asking your doctor to provide you with a peak flow meter, a simple device that measures the amount of breath in your lungs.

Most childhood asthma is caused by an allergy

Most childhood asthma is caused by an allergy. Skin-prick and RAST tests may be able to discover the allergen. Practical steps can then be taken to avoid it, be it house dust mites, cats, dogs or other pets. Even mould spores and pollen grains can trigger seasonal asthma attacks.

If you're prone to sudden or severe asthma attacks, keep asthma diary cards and a peak flow meter on hand to monitor your lung airflow so you can take early action.

Discuss an asthma action plan with your GP, who may issue an emergency supply of oral steroid pills. You may need to increase your medication dosage if your peak flow measurement drops steadily.

Remember, never stop taking your preventer medication, even when your symptoms are stable. Don't wait until your symptoms get worse - they'll be harder to treat.

For advice and support in understanding and managing your condition, contact Asthma UK.

This article was last medically reviewed by Dr Adrian Morris in September 2007.
First published in September 1999.

Thanks to Royal Brompton & Harefield NHS Trust for allowing BBC Health to take photos.