What is asthma?

Asthma is a chronic inflammatory condition of the airways. The airways in people with asthma are very sensitive and react to a variety of different stimuli. These reactions cause the airways to narrow or become completely blocked preventing normal breathing.

According to Asthma UK asthma affects one in every five households in the UK. Overall, there are thought to be some 5.4 million people receiving treatment for asthma in the UK, including 1.1m children.

Asthma that is related to allergies (atopic asthma) often starts in childhood. The tendency to develop asthma runs in families and the chances of a child developing asthma are higher if both parents have it. There is also a link between eczema, hay fever and asthma and often children will have a combination of these conditions. Some children will grow out of asthma while others will not.

Asthma can also be triggered by other factors that are not allergies - this type usually occurs in adults.

What are the symptoms of asthma?

The symptoms of asthma are caused by narrowing of the airways. This occurs when the muscles of the airways contract in response to certain trigger factors such as inhaling cigarette smoke or exercising. In addition, the lining of the airways becomes red and inflamed and produces sticky mucus, restricting the function of the airways further.

Forcing air through restricted airways may cause a wheezing sound and the production of excess mucus may irritate the airways and cause coughing. The chest will feel tight and breathing becomes difficult. Asthma symptoms may be mild and relieved fairly quickly with medication or they may be severe requiring urgent medical attention.

What causes asthma?

Asthma can be triggered by many different things. It is important for the child or person with asthma to learn which things commonly trigger their asthma and then try to avoid them.

  • Colds and other viral infections are among the most common triggers for asthma. Some children may only get asthma symptoms when they have an infection.
  • House-dust mites are more likely to affect older children and adults.
  • Allergy to furry pets like cats and dogs is common, particularly in children
  • Cigarette smoke significantly increases breathing problems in people with asthma. People with asthma should not smoke and studies have proved that children whose mothers smoke are more likely to develop asthma.
  • In some people asthma is triggered by exercise. This is known as exercise-induced asthma.
  • Stress or strong emotions such as excitement or anger can also trigger asthma attacks in some children and adults.
  • Hormonal changes in women, such as in pregnancy, can affect asthma.
  • Poor air quality and pollen in the air often affect asthma sufferers, as can cold, windy weather.

What treatment is available?

There are two main types of treatment: short-acting medicine which relieves asthma during an attack (bronchodilators); and longer acting or preventative medicine which helps to stop symptoms from occurring (eg, inhaled steroids).

Treatment can be given in various forms. Usually, the first treatment your doctor will prescribe is an inhaler that can be used during an attack to relax the muscles and widen the airways, or to prevent symptoms occurring when a known trigger is present, eg, before exercise. The inhaler will contain a type of bronchodilator called a beta-agonist. Short-acting beta-agonists include salbutamol and terbutaline. There are various types of inhaler devices available, including accuhalers, clickhalers and turbohalers.

If you are using an inhaler containing a short-acting beta-agonist more than three times a week a steroid inhaler will usually be added to your treatment. Steroid inhalers act as a preventative, by reducing the sensitivity of the airways to triggers. They also reduce inflammation and mucus production when symptoms do occur. Steroids such as beclometasone, budesonide, ciclesonide, fluticasone and mometasone need to be taken on a regular basis to be effective in reducing asthma symptoms. These steroids are corticosteroids, which are produced naturally in the body, not anabolic steroids (the type associated with body building).

Long-acting beta-agonists such as bambuterol, formoterol and salmeterol may be used for longer control while exercising or to relieve symptoms overnight. These will usually be added to therapy if treatment with an inhaled steroid plus a short-acting beta-agonist used when required is not sufficient. Vilanterol is another inhaled long-acting beta-agonist that is available only in combination with the steroid fluticasone.

In patients who still experience symptoms despite taking an inhaled steroid and a long-acting beta-agonist, another type of long-acting bronchodilator called tiotropium may also be prescribed.

Other drugs that may be added to therapy to control asthma include aminophylline, theophylline and oral beta-agonists (tablets, capsules or syrup). Montelukast (eg, Singulair®) and zafirlukast (Accolate®) tablets are anti-inflammatory medicines that can be given as additional therapy if inhalers are not sufficient.

Mepolizumab (Nucala®), omalizumab (Xolair®) and reslizumab (Cinqaero®) are injectable medicines that may be added to therapy in suitable patients.

If the asthma becomes fairly severe, a short course of steroid tablets may be prescribed. These will contain a drug called prednisolone.

A peak flow meter is a device which measures how well your lungs can expel air. Your doctor will explain how to use it. The device will give you a peak expiratory flow rate (PEFR) score. PEFR scores vary according to age, sex and height. You will probably be given a chart on which to record your PEFR score at different times of the day before the inhalers are used. The PEFR scores will indicate how well your asthma treatment is working and will help your doctor to monitor how your asthma is being controlled. They will be useful if a new treatment is given.

Self-help measures

  • Always ensure that you have sufficient supplies of medication, particularly if you are travelling. A spare inhaler is a good idea in case you lose one.
  • Take preventative medicine regularly to enable it to work effectively.
  • Exercise may trigger asthma, but should not prevent you from exercising as most symptoms can be controlled with the correct preventative medicine. However, you should check with a medical expert first. Swimming and yoga are particularly good for people with asthma.
  • Moving house will not relieve asthma symptoms - air quality is not the only trigger and there are people affected by asthma even in the least polluted areas of the UK.
  • Try to avoid trigger factors such as cigarette smoke or furry household pets.
  • House-dust mites are a common trigger and live in house dust. Covers can be applied to mattresses, duvets and pillows; wash soft toys regularly - putting them in the freezer for 24 hours will kill any mites; vacuum all carpets regularly - lino or tiled floors may be more suitable; damp dusting of surfaces can keep dust levels down.
  • Some people may have a food allergy which can increase symptoms - your doctor can refer you for tests if a food allergy is suspected.

Further information available from:

Asthma UK 
18 Mansell Street
London E1 8AA
Tel: 020 7786 4900
Asthma UK Adviceline: 0800 121 6244

Fact sheet provided by MIMS

Date last reviewed: July 2014

Read these next

New injectable antibody treatment for asthma

New injectable antibody treatment for asthma

Cinqaero (reslizumab) can be prescribed as add-on therapy...

New antibody treatment for severe asthma

New antibody treatment for severe asthma

Nucala (mepolizumab) can be prescribed as an add-on...

Register or Subscribe to MIMS

GPs can get MIMS print & online and GPonline for free when they register online – take 2 minutes, and make sure you get your free MIMS access! If you're not a GP, you can subscribe to MIMS for full access.

Register or subscribe

MIMS bulletins

News and updates straight to your inbox.

Prescribing Update: Fortnightly news bulletin
Urgent prescribing updates
Spotlight: Disease-themed monthly round-up

Sign me up

MIMS Dermatology

Read the latest issue online exclusively on MIMS Learning.

Read MIMS Dermatology

Mobile apps

MIMS: access the full drug database and quick-reference tables on the go

MIMS Diagnosis and Management: concise information on signs and symptoms, investigations and diseases

Promo Image

Clinical calculators

Handy calculators and conversions for primary care.