Asthma FAQ: Clear Answers to Common Questions

Asthma is a long-term condition in which the airways in the lungs can become inflamed and narrowed, making it hard to breathe. About 27.8 million people in the U.S. had asthma in 2023, according to the CDC. There’s no cure, but with the right treatment and an asthma action plan, most people can keep it under control.

This FAQ answers the questions people ask most, from triggers and diagnosis to medicines and allergies. For more, see our asthma guides.

Jump to: Quick facts · Basics · Triggers · Diagnosis · Treatment · Allergic asthma · Emergencies · More questions

Quick facts

Sources: CDC national asthma data and the National Heart, Lung, and Blood Institute (NHLBI).

The basics

What is asthma?

The NHLBI describes asthma as a chronic condition that affects the airways in the lungs. During flare-ups, the airways can become inflamed and narrowed, which makes it harder to breathe out.

What does an asthma attack feel like?

The NHLBI lists wheezing (a whistling sound when you breathe out), coughing especially at night or early morning, shortness of breath and chest tightness. An attack may start with coughing and a tight chest, and you may feel lightheaded. Many people with asthma also notice symptoms get worse at night; a 2018 review notes nighttime worsening affects more than two-thirds of people with asthma.

Can asthma go away?

There’s no cure, according to the NHLBI. Symptoms can be well controlled with treatment, and they may vary over time. Asthma often begins in childhood.

Triggers

What triggers asthma?

The NHLBI lists pollen, exercise, viral infections and cold air among common triggers. Others include:

• Indoor allergens: dust mites, mold and pet dander. See mattress and pillow covers and humidity control.
• Air pollution: ozone and particle pollution. See ozone and asthma and AQI and asthma.
• Irritants: tobacco smoke, strong scents and cleaning sprays. See spray cleaners and asthma.

Can people with asthma exercise?

Exercise can trigger symptoms, but staying active is still important. Talk to your doctor about a plan that keeps your asthma controlled during exercise. On high-ozone or smoky days, the EPA advises shorter, less intense outdoor activity for people with asthma.

Diagnosis

How is asthma diagnosed?

The NHLBI lists these tests:

• Spirometry: measures how much air you can breathe out and how fast.
• Bronchodilator test: checks how much better you can breathe out after a fast-acting inhaled medicine.
• FeNO test: measures nitric oxide in your breath; high levels may mean inflamed airways.
• Allergy testing: finds allergens, such as pet dander or pollen, that cause a reaction.
• Challenge tests: assess how sensitive your airways are.

Most diagnostic tests don’t work well for young children, which can make diagnosis harder at that age.

Treatment

What medicines treat asthma?

The NHLBI describes two main types:

• Quick-relief medicines (relievers), such as inhaled short-acting beta2-agonists, ease symptoms during an attack.
• Long-term control medicines, taken daily, help prevent attacks. Inhaled corticosteroids are one example; they can cause a hoarse voice or thrush.

What is an asthma action plan?

A written plan from your provider that covers your triggers, how to recognize an attack, which medicines to take and when, and when to call your provider or go to the emergency room.

Do inhaled steroids affect children’s growth?

They can slightly slow growth, mostly in the first year. A long-term study found adult height was about 1.2 cm lower after several years of budesonide. See does Pulmicort reduce height?

Allergic asthma

What is allergic asthma?

Asthma that is triggered by allergens such as pollen, dust mites, mold or pet dander. Allergy testing can show which allergens matter for you, so you can target avoidance and treatment.

Can allergy treatment help asthma?

Treating allergies and reducing exposure can help. Allergy shots treat seasonal allergic asthma and indoor allergens such as dust mites (Mayo Clinic). See allergy drops vs shots.

Emergencies

When is asthma an emergency?

Follow the emergency steps in your asthma action plan. The NHLBI says to call 911 if your medicines aren’t relieving symptoms during an attack or breathing is still very hard. In young children, also call 911 if they seem drowsy, confused or troubled, have a blue tint to the skin and lips, or have a fast heartbeat.

This guide is general information, not medical advice. Read our medical disclaimer.

More questions

How common is asthma?

About 8.4% of people in the U.S., or 27.8 million, had asthma in 2023, including 4.8 million children (CDC).

Is asthma contagious?

No. Asthma is a chronic condition of the airways. Viral infections, which are contagious, can trigger asthma symptoms.

Can asthma start in adulthood?

Yes. Although it often begins in childhood, adults can develop asthma too. See adult-onset allergies.

Why is my asthma worse at night?

Daily rhythms in lung function and lying down both contribute, and bedroom allergens like dust mites can play a role. See how to sleep better with allergies.

Does a bronchial thermoplasty procedure help severe asthma?

It’s an option for some adults with severe asthma. See Alair bronchial thermoplasty.

Sources

• Centers for Disease Control and Prevention. Most recent national asthma data. Updated October 6, 2026.
• National Heart, Lung, and Blood Institute. What is asthma? Updated April 17, 2024.
• National Heart, Lung, and Blood Institute. Asthma: diagnosis. Updated April 17, 2024.
• National Heart, Lung, and Blood Institute. Asthma attacks. Updated April 17, 2024.
• National Heart, Lung, and Blood Institute. Asthma: treatment and action plan. Updated April 17, 2024.
• Mayo Clinic Staff. Allergy shots. April 13, 2024.
• Francisco CO, Bhatawadekar SA, Babineau J, et al. Effects of physical exercise training on nocturnal symptoms in asthma: systematic review. PLoS One. 2018;13(10):e0204953.

Last reviewed: October 21, 2026.