What's making me wheeze? Patsy Westcott Different people have different triggers. It might be cold air, smoke, house dust mites or even your emotions.

In this article

Identifying triggers Airborne irritants Cigarette smoke

Cold air Drugs

Emotions House dust mites

Trigger factors, such as allergens and activities, can bring on asthma symptoms. Some triggers involve specific irritants, such as cigarette smoke, certain foods or chemicals, while others are non-specific, such as cold air, exercise and emotions.

Often more than one trigger is involved. For example, if you're sensitive to certain foods, these can make your bronchi more sensitive, if you then breathe in cigarette smoke it can trigger an attack.

A good way to identify your triggers is to keep a diary and write down any symptoms (such as cough, wheeze, difficulty breathing, peak flow readings) together with any potential triggers you've been exposed to (such as traffic fumes, a change in the weather, a cold or cough).

Show these notes to your doctor or practice nurse. You may also wish to ask your doctor about allergy testing as it may be useful.

Knowing how to avoid your triggers can help you to reduce the likelihood and intensity of an attack.

If your asthma is caused by an allergy, you may be able to find out what you're allergic to by having special tests and then taking practical steps to avoid the allergen.

Remember, never stop taking your preventer medication, even when your symptoms are stable.

Any substances you breathe in can become an allergen. These might include:

• Traffic fumes
• Smoke from cigarettes, bonfires and incinerators
• Animal dander, for example from dogs and cats
• Pollen, from trees and grasses
• Industrial fumes (especially those containing sulphur dioxide)
• Paint fumes
• Household chemicals, such as those found in air fresheners and aerosols
• Natural gas, fumes from cavity wall insulation
• Perfumed cosmetics
• Strongly scented flowers

Check for information on air pollution levels by calling the Department for Environment, Food and Rural Affairs pollution helpline on 0800 556 677. For the latest on pollen counts in the UK visit BBC Weather.

Cigarette smoke contains a number of different chemicals and gases that can irritate the lungs. The more inflamed your lungs, the greater the risk cigarette smoke will make your symptoms worse.

Some ways to reduce the effects of cigarettes:

• Stop smoking. This is especially important if you're a parent or planning to have a baby. Children whose mothers smoke are more likely to have asthma.
• Avoid passive smoking as best you can. Always have your reliever with you.
• Ask people not to smoke in your presence, especially if you start to develop asthma symptoms.

This is a non-specific trigger. Changes in air temperature, especially going from a warm room into cold air outside, often provoke symptoms. You could try to do the following:

• Take a couple of puffs of your reliever before going outside
• Cover your mouth and nose with a scarf
• Use your preventer exactly as prescribed to reduce the risk of attacks due to cold air

Certain prescription and over-the-counter drugs may trigger asthma attacks. They include aspirin and non-steroidal anti-inflammatory drugs such as ibuprofen and beta blockers used to treat heart disease and glaucoma. You should:

• Avoid drugs that may cause asthma symptoms
• Always remind your doctor about your asthma when being prescribed drugs
• Tell the pharmacist you have asthma if you're buying over-the-counter drugs

Crying, getting excited or upset, and even laughing can all trigger symptoms, especially in small children. Using your medicines as recommended by your doctor will help you avoid problems.

These tiny animals live on discarded flakes of human skin. Although some people with asthma react to the mites themselves, most are sensitive to the layer of protein that covers the mites' faeces.

Old sofas, armchairs, mattresses and fitted carpets all harbour mites, which thrive in the warm, damp atmosphere of today's centrally heated homes.

Although it's impossible to eliminate house dust mite dung entirely, there are many things you can do to reduce it:

• Hard floors, such as lino, wood or tiles, are easier to clean and keep dust free than carpets.
• Rugs should be washed regularly and hung out to dry in the sunshine.
• Special mattress and pillow covers are available. Wash blankets and duvets regularly and hang outside to dry.
• Air your bedroom daily by opening windows to reduce moisture levels and wash curtains regularly.
• Soft toys should be washed and dried (preferably) in a tumble dryer. Placing them in a plastic bag in your freezer, one day a week, will also help keep mites at bay.

This article was last medically reviewed by Dr Rob Hicks in August 2006.
First published in May 2001.