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Disease

Asthma

Learn about asthma, including its symptoms, diagnosis, laboratory tests, treatment and prevention.

Last Reviewed 27 Jul 2026
Reading Time 8 min read

Overview

A cough that will not quit, especially at night, or a tight, breathless feeling after running or in cold air, these are often the first signs of asthma, a condition affecting the airways rather than the lungs failing outright. It is extremely common, and with the right inhaler and a bit of know-how, most people with asthma live completely normal, active lives.

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Key Fact

In 2023, life-saving asthma inhalers were not available in public health facilities in more than a third of low- and lower-middle-income countries, and steroid inhalers were missing in more than half. Most asthma deaths happen not because the condition cannot be treated, but because treatment was not available when it was needed.

Warning

Severe difficulty breathing, being unable to speak in full sentences, or blue-tinged lips are signs of a serious asthma attack and need emergency care immediately. Do not wait to see if a reliever inhaler starts working.

AT A GLANCE

Disease Summary

Category Non-Communicable Disease
Cause Chronic inflammation and narrowing of the airways, arising from a combination of genetic and environmental factors
Transmission Not applicable; asthma is a non-communicable condition and cannot be spread between people
Body System Respiratory System
Preventable Yes
Curable No

Symptoms

Common Symptoms

Symptoms can be mild or severe and often come and go over time, sometimes worsening with a cold or a change in weather.

Persistent Cough

Especially at night, a cough that lingers or keeps returning is a common sign of asthma.

Wheezing

A whistling sound when breathing out, and sometimes breathing in, is one of the more recognisable signs.

Shortness of Breath

Difficulty breathing, sometimes even while resting, can occur during a flare-up.

Chest Tightness

A tight, squeezed feeling in the chest can make it difficult to breathe deeply.

Danger Signs

Seek emergency medical attention immediately if any of the following develop.

Severe Difficulty Breathing

Rapid, laboured breathing that does not improve with a reliever inhaler is a medical emergency.

Unable to Speak in Full Sentences

Being too breathless to complete a sentence indicates a severe attack.

Blue Tinge to the Lips or Fingertips

A sign that the blood may not be carrying enough oxygen, a medical emergency.

No Improvement After Using a Reliever Inhaler

If symptoms do not improve, or worsen, after using a reliever inhaler, seek emergency care immediately.

Diagnosis

Clinical History

Doctors ask about the pattern of symptoms, what triggers them, and whether asthma or allergies run in the family.

Lung Function Test (Spirometry)

Measures how much air you can breathe out and how quickly, and whether this improves after using a bronchodilator.

Peak Flow Measurement

A simple, handheld device that measures how forcefully you can breathe out, useful for tracking asthma control over time.
Important
There is no single test that confirms asthma on its own. Diagnosis usually combines the pattern of symptoms with lung function testing, since several other conditions can cause similar symptoms.

Laboratory Tests

Spirometry

Measures lung function and checks whether airflow improves after using a bronchodilator, a key part of confirming asthma.

Sample Breathing test, non-invasive
Time A few minutes

Peak Flow Measurement

A simple daily or clinic-based test that tracks how well the airways are functioning over time.

Sample Breathing test, non-invasive
Time Immediate

Allergy Testing

Identifies specific allergens that may be triggering symptoms, such as dust mites or pollen.

Sample Skin prick test or blood test
Time Same day to a few days

Chest X-ray

Not used to diagnose asthma directly, but can help rule out other causes of breathing difficulty.

Sample Imaging, no sample required
Time Same day

Laboratory Note

Asthma is diagnosed mainly through breathing tests and the pattern of symptoms rather than a blood test. Additional tests are sometimes used to identify triggers or rule out other conditions.

Treatment

Reliever Inhaler (Bronchodilator)

Opens the airways quickly to relieve symptoms during a flare-up. Every person with asthma should have one readily available.

Route Inhaled
Duration Used as needed during symptoms or attacks

Preventer Inhaler (Steroid)

Reduces inflammation in the airways over time, lowering the risk of attacks. This is the medication most linked to preventing severe attacks and death, yet it is the one most often unavailable in under-resourced areas.

Route Inhaled
Duration Used daily, often long-term

Treatment Note

A spacer device, a simple chamber attached to an inhaler, makes it easier for the medication to reach the lungs, especially for children. A homemade spacer made from a clean 500ml plastic bottle can work as well as a commercially made one, an option worth knowing about where cost or access is a barrier.

Prevention

Reduce exposure to tobacco smoke

Avoiding tobacco smoke, including secondhand smoke during pregnancy and childhood, lowers the risk of developing asthma and reduces flare-ups.

Identify and avoid personal triggers

Dust, mould, pollen, strong fumes, and pet fur are common triggers. Knowing your own triggers helps prevent flare-ups.

Use preventer medication consistently

Taking a prescribed steroid inhaler daily, even without symptoms, significantly reduces the risk of severe attacks.

Follow an asthma action plan

A written plan from a healthcare provider helps you recognise worsening symptoms early and know exactly what to do.

Prevention Note

While asthma itself cannot always be prevented, asthma attacks very often can be, through consistent use of preventer medication and awareness of personal triggers.

Risk Factors

Higher Risk

These factors increase the likelihood of developing asthma.

  • A close family member with asthma
  • Other allergic conditions, such as eczema or hay fever
  • Low birth weight or premature birth

Environmental Risk Factors

Exposures linked to a higher risk of asthma or worse symptoms.

  • Exposure to tobacco smoke, including before birth
  • Indoor and outdoor air pollution
  • Occupational exposure to dust, fumes, or chemicals

Other Contributing Factors

Additional factors linked to asthma risk.

  • Being overweight or living with obesity
  • Living in an urban area
  • Frequent viral respiratory infections in early childhood

Risk Note

Having one or more risk factors does not mean asthma is inevitable, and many people with asthma have no clear family history at all.

Complications

Severe Asthma Attacks

Can require emergency treatment or hospitalisation, and in the most serious cases, can be fatal.

Sleep Disruption and Fatigue

Frequent night-time symptoms can lead to poor sleep, tiredness, and difficulty concentrating.

Reduced Lung Function Over Time

Poorly controlled asthma over many years can lead to lasting changes in the airways.

Complication Note

Most of these complications are preventable with consistent use of preventer medication and a clear asthma action plan, which is why ongoing management matters even when symptoms feel mild.

When to Seek Medical Care

Severe Difficulty Breathing

Needs emergency medical attention immediately.

No Improvement After Using a Reliever Inhaler

If symptoms persist or worsen after treatment, seek emergency care.

Frequent Night-Time Symptoms

Regularly waking due to coughing or breathlessness suggests asthma is not well controlled and needs review.

Needing a Reliever Inhaler More Than Twice a Week

Can indicate that preventer treatment needs to be adjusted.

Emergency Advice

Well-controlled asthma should rarely interfere with daily life. Needing rescue treatment often, or having symptoms that limit activity, are signs that a treatment plan needs to be reviewed with a healthcare provider.

Prognosis

Highly Manageable With Treatment

Most people with asthma can lead full, active lives with the right inhaler and a clear action plan.

Cannot Be Cured, But Can Be Well Controlled

Asthma is a lifelong condition, though symptoms can be minimal or absent for long periods with good management.

Outcomes Depend Heavily on Access to Treatment

Most asthma deaths occur in places where inhaled medication is not consistently available, not because the condition itself is especially deadly when properly treated.

Prognosis Note

Asthma affected an estimated 363 million people worldwide in 2023. With reliable access to inhaled medication and clear guidance on managing triggers, the vast majority of asthma deaths are preventable.

Differential Diagnosis

Chronic Obstructive Pulmonary Disease (COPD)

Causes similar breathing difficulty but usually develops later in life, often linked to long-term smoking, and does not improve as fully with bronchodilators.

Pneumonia

Can cause cough and breathlessness, but typically also involves fever and is confirmed through imaging rather than breathing tests.

Tuberculosis

Can cause a persistent cough in the same regions and should be considered, particularly if the cough is accompanied by weight loss or night sweats.

Clinical Note

Because several conditions can cause cough and breathlessness, a clear pattern of symptoms alongside lung function testing helps confirm asthma rather than relying on symptoms alone.

References

World Health Organization (WHO)

World Health Organization fact sheet on asthma causes, symptoms, treatment, and the global treatment access gap.

Global Initiative for Asthma (GINA)

Global clinical guidance and awareness resources on asthma diagnosis and management.

WHO Package of Essential Noncommunicable Disease Interventions (PEN)

WHO’s primary care protocols for assessing, diagnosing, and managing asthma and other chronic respiratory diseases in low-resource settings.

Frequently Asked Questions

Can asthma be cured?
No, asthma cannot be cured, but it can be very well controlled with the right inhaler and an asthma action plan. Most people with well-managed asthma live completely normal, active lives.
What should I do during an asthma attack?
Use your reliever inhaler right away, following your asthma action plan. If symptoms do not improve, you cannot speak in full sentences, or your lips turn blue, seek emergency care immediately.
Do I need to use my inhaler every day if I feel fine?
If you have been prescribed a daily preventer inhaler, yes. It works by reducing inflammation over time, and stopping it, even when you feel well, increases the risk of a severe attack.
Can children outgrow asthma?
Some children have fewer or milder symptoms as they get older, though the underlying tendency toward airway sensitivity often remains. Asthma can also develop or return at any age.