Key facts
- Asthma is a major noncommunicable disease (NCD), affecting both children and adults, and is the most common chronic disease among children.
- Inflammation and narrowing of the small airways in the lungs cause asthma symptoms, which can be any combination of cough, wheeze, shortness of breath and chest tightness.
- Asthma affected an estimated 262 million people in 2019 (1) and caused 455 000 deaths.
- Inhaled medication can control asthma symptoms and allow people with asthma to lead a normal, active life.
- Avoiding asthma triggers can also help to reduce asthma symptoms.
- Most asthma-related deaths occur in low- and lower-middle-income countries, where under-diagnosis and under-treatment is a challenge.
- WHO is committed to improving the diagnosis, treatment and monitoring of asthma to reduce the global burden of NCDs and make progress towards universal health coverage.
Overview
Asthma is a chronic lung disease affecting people of all ages. It is caused by inflammation and muscle tightening around the airways, which makes it harder to breathe.
Symptoms can include coughing, wheezing, shortness of breath and chest tightness. These symptoms can be mild or severe and can come and go over time.
Although asthma can be a serious condition, it can be managed with the right treatment. People with symptoms of asthma should speak to a health professional.
Impact
Asthma is often under-diagnosed and under-treated, particularly in low- and middle-income countries.
People with under-treated asthma can suffer sleep disturbance, tiredness during the day, and poor concentration. Asthma sufferers and their families may miss school and work, with financial impact on the family and wider community. If symptoms are severe, people with asthma may need to receive emergency health care and they may be admitted to hospital for treatment and monitoring. In the most severe cases, asthma can lead to death.
Symptoms
Symptoms of asthma can vary from person to person. Symptoms sometimes get significantly worse. This is known as an asthma attack. Symptoms are often worse at night or during exercise.
Common symptoms of asthma include:
- a persistent cough, especially at night
- wheezing when exhaling and sometimes when inhaling
- shortness of breath or difficulty breathing, sometimes even when resting
- chest tightness, making it difficult to breathe deeply.
Some people will have worse symptoms when they have a cold or during changes in the weather. Other triggers can include dust, smoke, fumes, grass and tree pollen, animal fur and feathers, strong soaps and perfume.
Symptoms can be caused by other conditions as well. People with symptoms should talk to a healthcare provider.
Causes
Many factors have been linked to an increased risk of developing asthma, although it is often difficult to find a single, direct cause.
- Asthma is more likely if other family members also have asthma – particularly a close relative, such as a parent or sibling.
- Asthma is more likely in people who have other allergic conditions, such as eczema and rhinitis (hay fever).
- Urbanization is associated with increased asthma prevalence, probably due to multiple lifestyle factors.
- Events in early life affect the developing lungs and can increase the risk of asthma. These include low birth weight, prematurity, exposure to tobacco smoke and other sources of air pollution, as well as viral respiratory infections.
- Exposure to a range of environmental allergens and irritants are also thought to increase the risk of asthma, including indoor and outdoor air pollution, house dust mites, moulds, and occupational exposure to chemicals, fumes or dust.
- Children and adults who are overweight or obese are at a greater risk of asthma.
