Triggers of asthma in children

What is a trigger?

Triggers are things that bring on the symptoms of asthma. They don’t cause asthma, but if your child already has it, they can make the symptoms worse. You can have one or more asthma triggers. What sets off your asthma symptoms may be different to what sets off someone else’s. Everyone with asthma has their own personal mix of triggers. (Asthma UK 2016, British Lung Foundation 2016)

Why do asthma triggers sometimes not cause symptoms?

The sensitivity of your airways can vary day to day, month to month, year to year. If your asthma’s well managed, your triggers are less likely to cause symptoms.

Also, your asthma symptoms can be caused by more than one asthma trigger at the same time. If this happens, it could cause a stronger reaction - for example, if you have a cold and you also come into contact with a cat. This can be why sometimes triggers do cause symptoms and why sometimes they don’t.

How do you know which asthma triggers affect you?

If you understand which things trigger your asthma you might be able to avoid them. Sometimes it’s obvious what your triggers are. Sometimes it’s not. Asking yourself these two questions can help you work out which triggers affect you:

1. HAVE I GOT ANY OBVIOUS TRIGGERS?

Often it’s obvious which things trigger your asthma - for example, when your symptoms start after you’ve come into contact with a cat or dog. Or you might find that your asthma symptoms are set off by a food allergy, alcohol, cigarette smoke or smoke from open fires.

2. WHAT ARE YOUR OTHER TRIGGERS?

Sometimes it’s not easy to pinpoint exactly what triggers your asthma. This is because some triggers are invisible (such as grass pollen); you may have more than one trigger; and sometimes you may have a delayed reaction to a trigger. A bit of extra detective work may be needed - try keeping a diary of activities and symptoms to help you spot any patterns (British Lung Foundation 2016)

Types of triggers

Cold & flu

Why can they increase your risk of asthma symptoms or an asthma attack?

Although experts have known for some time that colds and flu can raise your risk of having an asthma attack, the exact reason for the link hasn't been well understood. The latest research we have suggests that when people with asthma get a cold or flu, there's a rise in levels of an inflammatory protein in the cells that line the airways. This can set off a range of other inflammatory reactions, including narrowing of the airways, which can lead to an asthma attack.

Weather

People with asthma have airways that are very sensitive. Cold or damp air can enter the airways and trigger them to go into spasm, causing asthma symptoms, such as coughing, wheezing, shortness of breath and tightness in the chest. And winter can be a difficult time for people with asthma for other reasons too. It's near-impossible to avoid the cold and flu viruses that many people say make their asthma symptoms worse, although being vaccinated against flu each year can prevent you getting the most common strain of flu virus.

Exercise

Why can exercise increase your risk of asthma symptoms or an asthma attack?

Usually, you breathe in through your nose, so the air is warmed and moistened. When you exercise, you tend to breathe faster and in through your mouth, so the air you inhale is colder and drier. In some people with asthma, the airways are sensitive to these changes in temperature and humidity and they react by getting narrower. This can lead to asthma symptoms, such as coughing, wheezing, a shortness of breath and tightness in the chest. Exercise is more likely to trigger asthma symptoms

if your asthma isn't well managed. This is sometimes known as exercise-induced asthma. The symptoms of exercise-induced asthma are the same, but are usually most intense after exercising and then gradually improve.

Emotions

Everyone feels emotions such as love, hate, anger, and excitement. Sometimes we react by expressing ourselves: for example, crying when we feel sad or laughing when we feel happy or excited. Asthma symptoms can be triggered by our emotions, and by the way we express them

Food

Why can food increase your risk of asthma symptoms or an asthma attack?

When you come into contact with a food allergen, your immune system overreacts and releases a chemical called histamine. The release of histamine causes the symptoms of an allergic reaction. These can include red, itchy, watery eyes and nose, sneezing, a scratchy or sore throat and itchy skin. For anyone with a food allergy, symptoms can also include wheezing and coughing. In people who have asthma, it can also trigger asthma symptoms such as coughing, tightness in the chest and difficulty breathing. And this is where it can get confusing, because it can be hard to tell the difference between an allergic reaction to a food and an asthma attack.

Pollution

Two thirds of people with asthma tell us poor air quality makes their asthma worse, which puts them at higher risk of an asthma attack.

Pollutants, such as the chemicals in traffic fumes, can quickly irritate the airways and trigger asthma symptoms. The tiny particles found in dust, soot, and diesel fumes are small enough to get right into the lungs, causing inflammation and making your asthma symptoms worse. Pollution can make you more sensitive to your usual asthma triggers.

Indoor Environment

Central heating Open fires Carpets Cleaning Decorating Building work and repairs Air filters and purifiers Humidifiers and de-humidifiers Good ventilation

Smoke

Anyone with asthma or other conditions affecting the lungs is likely to find second-hand smoke can be a trigger. This is because the chemicals in tobacco smoke irritate the airways and the lungs and trigger asthma symptoms.

Babies and children take more smoke into their lungs than adults. Because they're still growing and their immune system isn't fully developed yet, they're at greater risk from the toxins given out in the smoke. Babies and small children exposed to tobacco smoke are more likely to have respiratory infections and wheeze, and are more likely to go on to develop asthma as they get older. Older children diagnosed with asthma or being treated for asthma are at a high risk of smoke triggering asthma symptoms or an asthma attack. When you smoke, or breathe in smoke, you're taking the smoke right into your lungs. The chemicals in cigarette smoke irritate and inflame the airways and lungs. If you're a smoker, or regularly exposed to tobacco smoke, you'll have more symptoms and need more medicines to keep on top of your asthma. If your asthma symptoms get worse you're at risk of an asthma attack.

Alcohol

Alcoholic drinks contain a natural food chemical called histamine, which is found at particularly high levels in red wine and some beers. Histamine is the same substance thats released in the body when you have an allergic reaction. In some people, the histamine in alcohol may trigger asthma symptoms.

Female hormones

There are certain times in a woman's life when hormone levels go up and down a lot. It is not known exactly why these hormonal changes affect asthma symptoms, or why they affect some women but not others. One theory is that they may directly affect the airways and/or cause the body to have a stronger inflammatory response to infection, but more research is needed before we can know for certain.

Mould & funghi

Around 37 per cent of people with asthma tell us mould and fungi can trigger their asthma If you have cold-like symptoms that don't end when seasons change, you may be allergic to the spores of mould or other fungi.

Fungi, including moulds, release 'seeds' called spores in to the air. Outside they're usually spread by the wind. Spore numbers increase when there's a sudden rise in temperature in a moist environment, such as when central heating is turned on in a damp house, when wet clothes are dried next to a radiator or when the sun comes out after it's been raining on a warm day.

Drugs

Drugs can make your asthma worse, trigger symptoms and lower your mood (which can trigger your asthma). Drugs can affect your asthma in ways you may not expect. For example, ecstasy or speed can make you feel more energetic so you may find yourself dancing longer. This increased activity may bring on asthma symptoms. Smoking cannabis can make you feel anxious, which can bring on asthma symptoms. Research has shown that cocaine use (both snorted and smoked) can lead to much worse asthma symptoms and asthma attacks. Smoking cigarettes and cannabis can trigger asthma symptoms and lead to long-term lung damage.

Stress & Anxiety

Stress causes a surge of stress hormones in our bodies. These are released to prepare us to either run away from danger or fight it (the "fight or flight" response). We react with symptoms such as a faster heart rate, tense muscles and breathing that is shallow and fast (hyperventilating). This change to our breathing pattern can put us at a higher risk of all our usual asthma symptoms, such as tight chest and coughing.

Animals

"If animals are a trigger for your asthma you probably have what's known as 'allergic asthma'," says Samantha Walker, Asthma UK's Director of Research and Policy. The allergens (which cause the allergic reaction in some people) are actually proteins found in the animal's flakes of skin (dander) -

and are harmless for most people. In people who are sensitive to these proteins, touching or inhaling animal allergens causes the immune system to overreact and release a chemical called histamine, leading to an allergic reaction. Symptoms can include red, itchy and watery eyes and nose; sneezing; coughing; scratchy or sore throat; itchy skin; and most serious of all, difficulty breathing.

House dustmites

Why can they increase your risk of asthma symptoms or an asthma attack?

House dust mite droppings contain substances that can trigger reactions. They’re invisible to the naked eye and 90 per cent of people with asthma are sensitive to them.

How do you know it's a trigger?

You might notice that you or your child has more symptoms when dust is disturbed - for example, when you're cleaning, moving furniture or making a bed. Or you might simply find your asthma symptoms are often worse indoors.

Pollen

Pollen is a tiny powder-like substance produced by certain types of trees, grasses and weeds. It is spread by insects and the wind. An allergy to grass or hay pollen is known as hay fever. The term hay fever is now also widely used to include allergies to other pollens (such as trees and weeds).

Hay fever and asthma are closely linked. Research results vary but its thought that between 20 per cent and 60 per cent of people with hay fever also have asthma. Approximately 80 per cent of people with asthma also have a pollen allergy (which means their asthma symptoms are triggered by pollen).

Sex

Why can sex increase your risk of asthma symptoms or having an asthma attack?

Sex, or any sexual activity, can sometimes trigger symptoms in people with asthma for different reasons. When you're sexually excited, your breathing gets quicker and changes (you might start breathing through your mouth) and this can trigger asthma symptoms.