Asthma

What happens in asthma

In asthma, the lining of the airways is chronically inflamed. When exposed to a trigger, three things narrow the airways:

1. Bronchospasm: the muscle around the airways tightens.
2. Swelling of the airway lining.
3. Extra mucus, which is thick and sticky.

This makes it hard to breathe out, which produces the whistling sound of wheeze and the feeling of tightness. Between flare-ups, breathing may be completely normal. Untreated inflammation over many years can cause permanent airway narrowing (airway remodeling).

Symptoms

• wheezing, a whistling sound when breathing out
• cough, especially at night, early morning, with exercise or after colds
• chest tightness
• shortness of breath

Patterns that suggest asthma rather than another condition:

• symptoms that vary over time and in intensity
• symptoms worse at night or early morning
• symptoms triggered by colds, exercise, allergens, cold air or laughter
• symptoms that improve with an asthma inhaler

Cough-variant asthma causes a chronic dry cough with little or no wheeze.

Types and patterns

• Allergic asthma: the most common type, often starting in childhood, with allergic rhinitis and eczema.
• Non-allergic asthma: often adult-onset, without clear allergic triggers.
• Exercise-induced bronchoconstriction: airway narrowing during or after exercise.
• Occupational asthma: caused or worsened by workplace exposures such as flour, wood dust, isocyanates in paints and latex.
• Aspirin-exacerbated respiratory disease: asthma, nasal polyps and reactions to aspirin and NSAIDs.
• Severe asthma: remains uncontrolled despite high-dose treatment; may need specialist and biologic therapy.

Triggers

Causes and risk factors

Asthma results from a combination of genes and environment:

• family history of asthma or allergies
• allergic conditions such as eczema, hay fever and food allergy
• exposure to tobacco smoke, including before birth
• viral chest infections in early childhood
• obesity
• workplace exposures
• air pollution

Diagnosis

There is no single test. A doctor combines your history with tests that show variable airflow limitation:

• Spirometry with bronchodilator: measures how much and how fast you can breathe out. An improvement of 12% or more (and 200 ml in adults) after a reliever inhaler supports asthma.
• Peak flow monitoring: twice-daily readings over 2 weeks showing large day-to-day variation.
• FeNO (fractional exhaled nitric oxide): high levels indicate allergic-type airway inflammation.
• Bronchial challenge test: inhaling methacholine or exercising to provoke narrowing, used when other tests are inconclusive.
• Allergy testing: skin-prick or blood tests to identify triggers.
• Chest X-ray: to exclude other conditions.

In children under 5, diagnosis is based mostly on the pattern of symptoms and the response to treatment, because breathing tests are difficult.

Treatment

The goals are few or no symptoms, no attacks, normal activity and normal lung function.

Inhalers

• Inhaled corticosteroids (ICS): the foundation of treatment. They reduce airway inflammation and the risk of severe attacks.
• ICS-formoterol combination inhalers: current international guidance (GINA) prefers an as-needed low-dose ICS-formoterol inhaler as the reliever for adults and teens, used alone in mild asthma or as both daily and reliever treatment (maintenance and reliever therapy) in more persistent asthma.
• Short-acting beta-agonists (SABA) such as albuterol: quick relief that works within minutes. Using a SABA alone, without an inhaled steroid, is no longer recommended for adults and teens because it does not treat inflammation.
• Long-acting bronchodilators (LABA, LAMA): added to ICS for persistent symptoms.

Other medicines

• Leukotriene receptor antagonists (montelukast): tablets used in some people, especially with allergic rhinitis. They carry an FDA warning about mood and behavior changes.
• Biologic injections for severe asthma, targeting IgE, IL-5, IL-4/IL-13 or TSLP.
• Oral corticosteroids: short courses for attacks. Frequent use has significant side effects, which is a sign treatment needs review.
• Allergen immunotherapy for some people with allergic asthma.

Inhaler technique and spacers

Many people use inhalers incorrectly, so less medicine reaches the lungs. A spacer with a metered-dose inhaler improves delivery and is standard for children. Ask a nurse, pharmacist or doctor to check your technique.

Asthma action plan

A written plan tells you your usual medicines, how to recognize worsening asthma, what to do in each zone (green, yellow, red) and when to get emergency help.

What to do during an asthma attack

1. Sit up straight and stay calm.
2. Take your reliever inhaler as directed in your action plan.
3. If you are not improving, keep using it as your plan instructs while you get help.
4. Call 911 or your local emergency number if you are not improving, are getting worse, or have any emergency signs.

Complications

• severe attacks needing hospital care, which can be fatal
• sleep disruption and missed work or school
• permanent airway narrowing
• side effects from frequent oral steroids
• pneumonia and other chest infections

Living with asthma

• Take your controller inhaler every day as prescribed, even when you feel well.
• Avoid smoking and smoke exposure.
• Get a yearly flu vaccine and stay current with COVID-19 and pneumococcal vaccines as recommended.
• Exercise regularly; warm up first and use your reliever beforehand if advised.
• Review your asthma at least once a year.
• Treat related problems such as allergic rhinitis, reflux, obesity and sleep apnea.

Asthma vs COPD

Some people have features of both.

Frequently asked questions

What are the first signs of asthma?

Early signs include a recurring cough (especially at night), wheezing, chest tightness and shortness of breath with exercise, colds or allergens. Symptoms that come and go and improve with an inhaler strongly suggest asthma.

Can asthma go away?

Asthma symptoms often improve or disappear in some children as they grow, and some adults have long symptom-free periods. The underlying airway sensitivity usually remains, so symptoms can return. Good control with treatment lets most people live normally.

What triggers an asthma attack?

Common triggers are colds and flu, allergens such as pollen, dust mites and pets, cigarette smoke, air pollution, exercise, cold air and some medicines such as aspirin. Not taking controller inhalers regularly also increases attack risk.

Can you develop asthma as an adult?

Yes. Adult-onset asthma is common and can be triggered by respiratory infections, workplace exposures, hormonal changes, obesity or allergies. It is often non-allergic and may need ongoing treatment. New wheeze or cough in an adult should be checked.

What is the best inhaler for asthma?

There is no single best inhaler. For most adults and teens, inhalers containing an inhaled corticosteroid are the key to control, often as an ICS-formoterol combination used as needed or daily. Your doctor will match treatment to how severe your asthma is.

Is asthma hereditary?

Asthma tends to run in families. If one or both parents have asthma or allergies, a child's risk is higher. Environmental factors such as smoke exposure, infections and allergens also matter, so not everyone with a family history develops it.