A trigger is anything that irritates the airways and causes the symptoms of asthma. Everyone’s asthma is different and you may have several triggers. An important aspect of controlling your asthma is avoiding your triggers.

It may be impossible to avoid all of your triggers but once you have identified them, there are things you can do to help you reduce unnecessary symptoms and better control your asthma.

It can be difficult to identify exactly what triggers your asthma. Sometimes the link is obvious, for example when your symptoms start within minutes of coming into contact with a cat or dog. But some people can have a delayed reaction to an asthma trigger, so some extra detective work may be needed.

Use the links in this section to find out more about possible triggers and how to avoid them.

Animals

Furry and feathery animals are a common trigger of asthma symptoms. The allergens (the thing that causes the allergic reaction) are found in their saliva, flakes of skin (pet dander), fur and urine.

If you know your asthma is triggered by furry or feathery animals

• Try and find a new home for your pet - and if you cannot find them a new home ensure that they don't go in your living room or bedroom
• Bathing cats and dogs twice a week can help. Ask your vet for advice on how to do this properly

Air pollutants

The air we breathe contains lots of different particles that can trigger asthma symptoms. Air pollutants like cigarette smoke and car exhaust fumes release gases and particles into the atmosphere, which can irritate your airways.

• If you find pollution triggers your asthma, keep well informed about air quality.
• Ozone can be a problem for some people. Levels are likely to be higher on hot, summer days. If you think this might be a trigger for you, avoid exercising outdoors, especially in the afternoon.

Colds & viral infections

Colds and viral infections are very common triggers of asthma. They are also almost impossible to avoid.

At your asthma review you should talk to your doctor or asthma nurse about having the flu vaccination. These are normally available every autumn.

People who are regularly taking steroid tablets should also talk to their doctor about having the pneumococcal vaccination.

Unlike the flu vaccination, which should be repeated every year, the pneumococcal vaccination is usually only given once.

Flu and pneumococcal injections are also recommended for everyone over the age of 65.

Emotions

Stress or even a fit of laughter can trigger asthma symptoms, as can other situations such as depression, financial problems, bereavement and extreme work-related stress. Monitoring your condition and taking your medicine regularly should help to minimize symptoms. Talk to your doctor or asthma nurse if you are going through a difficult time and feel you need more support

Exercise

Some people with asthma find that exercise triggers their asthma symptoms. However, exercise is good for everyone, including people with asthma. If your asthma is well controlled, you should be able to join in, have fun and keep fit.

If your asthma symptoms get worse during or after exercise it could be a sign that your asthma is poorly controlled and you may need to visit your doctor or asthma nurse for an asthma review.

Tips on exercising with asthma

• Make sure the people you are exercising with know you have asthma.
• Increase your fitness levels gradually.
• Always have your reliever inhaler with you when you exercise.
• If exercise triggers your asthma use your reliever inhaler immediately before you warm up.
• Ensure that you always warm up and down thoroughly.
• Try not to come into contact with things that trigger your asthma.
• If you have symptoms when you exercise, stop, take your reliever inhaler and wait until you feel better before starting again.
• If you use preventer medicine, take it as prescribed by your doctor or asthma nurse.

What are the best types of exercise for people with asthma?

If your asthma is under control, you should be able to do any sport or exercise that you enjoy. However, you might like to try the following:

• Yoga (helps to relax the body and improve your breathing technique)
• Fitness classes involving short periods of aerobic exercise
• Team sports such as football or hockey are less likely to cause asthma symptoms as they are played in brief bursts with short breaks in between.
• Swimming is usually an excellent form of exercise for most people with asthma. The warm humid air in the swimming pool is less likely to trigger symptoms of asthma. However, chlorine and swimming in cold water can trigger some people's asthma.

Food

Most people with asthma do not have to follow a special diet. In some cases, certain foods including cow’s milk, eggs, fish, shellfish, yeast products, nuts, and some food colourings and preservatives, can make symptoms worse.
If you think you have a food allergy, contact your doctor or asthma nurse for further advice.

Hormones

Some women find their asthma can be affected around puberty, before their periods, during pregnancy and during menopause. If your asthma gets worse around these times, see your doctor or asthma nurse so that you can discuss any changes to your medicines that may help.

House-dust mites

Many people with asthma are sensitive to the droppings of house-dust mites. These are tiny creatures that live in the dust that builds up around the house, in carpets, bedding, soft furnishings and soft toys.
If you know house-dust mites trigger your asthma, you may be able to reduce some symptoms by following all the recommendations below. However, if your symptoms do not improve using these measures, there is no point in continuing them.

• Use complete barrier covering systems on your mattress, duvet and pillow.
• Remove all carpets and replace with hard flooring.
• Vacuum all areas frequently. Use a vacuum cleaner that has good suction and a filtered exhaust that does not scatter dust. Damp dust all surfaces or use an attachment on your vacuum cleaner.
• Ask someone else to vacuum while you stay out of the room.
• Remove all soft toys from beds. Put them into a bag in the freezer for a minimum of six hours every one to two weeks to kill house-dust mites.
• Hot wash (at 60 degrees C) sheets, duvet covers and pillowcases once a week. Although some people are allergic to feathers, there is no conclusive evidence to show that synthetic, 'hypo-allergenic' pillows are any better.
• Clean your soft furnishings with anti-house-dust mite chemicals.
• Use a dehumidifier to dry the air, as this makes it more difficult for the house-dust mites to survive.

Medicines that may trigger asthma in some people

Some medicines that are used to treat a range of conditions can lead to asthma attacks in a small number of people.

These medicines include, aspirin and non-steroidal anti-inflammatory tablets such as brufen, voltarol and naposyn (for example Ibuprofen and Naproxin). Other medicines that can sometimes lead to asthma attacks include beta-blockers, used to treat heart disease and glaucoma and some cold and flu remedies

Moulds & fungi

Moulds release tiny seeds called spores into the air, which can trigger asthma symptoms in some people. Mould spores are found in any damp place – from piles of autumn leaves and woody areas, to bathrooms, kitchens and even piles of damp clothes.

To help avoid this trigger:

• Ensure the house is well ventilated.
• Ensure damp in the home is treated quickly.
• Avoid areas (such as gardens or compost) that may contain mould spores

Pollen

Pollen can trigger asthma symptoms in some people.
If your asthma is triggered by pollen, try the following to reduce your asthma in the pollen season:

• Review your treatment with your doctor or asthma nurse in advance of the hay fever season
• Look out for pollen forecasts on the television, in newspapers or on the internet - if high counts are forecast in your region, try to reduce the time you spend outside
• To help avoid pollen as a trigger for children's asthma do not stop your child from playing outside, but be aware that a high pollen count could cause problems

Sex

If you are concerned about your asthma symptoms becoming worse during sex, you can control your symptoms as you would with any form of exercise.

Smoking

Smoking is dangerous for everyone, but particularly for people with asthma. It can irritate the lungs and bring on asthma symptoms.

• If you smoke (or breathe in other people's smoke) you increase the risk of an asthma attack and may permanently damage your airways
• You are increasing the risk of your asthma persisting if you smoke as a teenager
• You are putting children at risk of asthma if you smoke around them or during pregnancy
• Many public places are now smoke-free areas but do not be afraid to ask other people to stop smoking around you

Weather

A sudden change in temperature, cold air, windy days, poor air quality and hot, humid days are all known triggers for asthma.

Take your usual dose of reliever inhaler before going out on cold, dry days. If it is cold and windy, wearing a scarf over your face will help to warm up the air before you breathe it in. Try to avoid going out in the middle of the day on hot, smoggy days.

Thunderstorms

Thunderstorms can release large quantities of pollen, in very small particles, into the air. This can trigger asthma attacks for many people. It is best to stay inside with the windows closed during thunderstorms