What is Asthma?

Asthma is a chronic lung disease that causes episodes of coughing, wheezing, chest tightness and shortness of breath. Asthma symptoms can be mild, moderate or severe, and sometimes life-threatening. When symptoms suddenly worsen, it is called an asthma attack. Like all chronic respiratory diseases, there is no cure for asthma. But in most cases, asthma is very manageable.

Illustration showing a statistic that 1 in 13 people in the U.S. live with asthma. It features a row of stylized figures with one highlighted and an image of a health professional standing to the side.
Illustration of a yellow school bus and a smiling child wearing a backpack. Text reads "1 in 10 U.S. school-aged children.
Illustration of a person with text: "10 deaths per day due to asthma" and "Black Americans are 3x more likely to die than other groups.

Asthma is not a one-size-fits-all disease. What sets off symptoms for you or someone in your family may be quite different from what affects someone else. When you understand what is happening inside your lungs and how your breathing responds to allergens and irritants like pollen, mold, dust mites or cigarette smoke, you can take steps to prevent or minimize symptoms.

What types of asthma are there?

Most people are diagnosed with one of two types of asthma. The diagnosis is based on medical history of what causes symptom, the severity of symptoms, and disease control.

  • Intermittent asthma: This is diagnosed when asthma symptoms arise and then go away. People with intermittent asthma may breathe normally between onset of symptoms.
  • Persistent asthma: This is diagnosed when symptoms tend to occur much of the time. They can be mild, moderate or severe.

Asthma can be diagnosed based on the age that symptoms first appear or what triggers symptoms.

  • Childhood asthma: Some children may be diagnosed with asthma as infants or babies. Many others are diagnosed before 5 years of age as their lungs continue to develop.
  • Adult-onset asthma: People may develop asthma as adults (after the age of 18). The diagnosis could be the result of several factors, including age, exposure to irritants or development of new allergies.
  • Allergic asthma: This is diagnosed when allergens cause symptoms. Common allergens include grass, tree and ragweed pollen, molds, pet dander, dust mites and pests such as cockroaches and mice. Allergic diseases and asthma often go hand-in-hand.
  • Nonallergic asthma: This is diagnosed when triggers do not involve allergens. Triggers could involve physical activity, exposure to air pollution, the flu or a cold virus, sudden changes in weather, or stress.
  • Exercise-induced asthma: This is a type of asthma triggered by exercise. It can affect people of any age. It’s also called exercise-induced bronchospasm.
  • Occupational asthma: This is a type of asthma that occurs in the workplace. It is diagnosed in people – primarily adults – who experience symptoms as a result of harmful irritants in their workplace environment.
  • Asthma-COPD Overlap (ACO): People who are diagnosed with both asthma and chronic obstructive pulmonary disease (COPD) have ACO. People whose lungs are damaged by poorly controlled asthma and exposure to irritants such as tobacco smoke are at increased risk of developing COPD.

A multi-generational family of six, including three adults and three children, sits together on grass in a park. They are smiling and dressed casually. Lush green trees are visible in the background, suggesting a sunny day.

Who is at risk of developing asthma?

Anyone of any age, family background, race, sex or general health can develop asthma. Studies show asthma is more common among boys than girls during childhood; in adulthood, it’s more common among women than men. Black Americans, Native Americans and certain Hispanic/Latino groups, particularly Puerto Ricans, experience asthma at higher rates than other races.

People with asthma who are regularly exposed to irritants such as polluted air or tobacco smoke (including secondhand smoke and thirdhand smoke) are at risk for asthma.

How many people have asthma in the United States? According to the U.S. Centers for Disease Control and Prevention (CDC), more than 25 million people live with asthma in the United States. It affects people of all ages: 8.4% of adults and 5.8% of children. In childhood, asthma is more common in boys than girls. In adulthood, it’s the reverse: more common in women than men. Asthma affects people of all ethnicities, but it has higher rates among Puerto Ricans, Black Americans, American Indians/Alaskan Natives, and people with multiple ethnicities.

What causes asthma?

Researchers think genetic and environmental factors play a role in asthma, especially during the first years of life when the immune system is under development.

Asthma risk factors may include:

  • Family history of asthma or allergies
  • Mother’s smoking or exposure to secondhand smoke or air pollution during pregnancy
  • Early childhood exposure to secondhand smoke, air pollution or indoor allergens such as dust mites, cockroaches or mold
  • Damage to developing lungs due to premature birth or early childhood respiratory illnesses
  • For adults, exposure to chemical irritants or industrial dust in the workplace

How does asthma affect the lungs and airways?

The airways inside your lungs look like an upside-down tree. The respiratory system is in the chest and is made up of several different parts:

  • Upper respiratory system – This is the nose, sinuses, and the parts of the airway called the pharynx and the part of the larynx above the vocal chords.
  • Lower respiratory system – This is the portion of the larynx below the vocal chords, the trachea, bronchi and bronchioles (all breathing tubes that get smaller and smaller – especially in the lower lungs)
Illustration of human lungs with visible bronchial tubes and surrounding veins and arteries, showcasing the respiratory system against a light background.

It’s important to understand that asthma is a syndrome and not just a single disease. Asthma affects the lungs in two ways:

Airway inflammation

Asthma begins with inflammation: The lining of the airways – the breathing tubes leading into the lungs – becomes swollen, inflamed. They then produce extra mucus which clogs the airways.

Asthma inflammation is the quiet part of asthma. When we talk about quiet asthma, that’s when the inflammation and swelling takes place. You can’t feel or see what’s going on, but each time you are exposed to your asthma triggers, your airways react and inflammation increases and your breathing problems are likely to get worse.

Illustration comparing a normal airway with smooth, open passages on the left to a bronchospasm on the right, showing narrowed airways with constricted muscles and inflamed tissue.

Bronchospasm

Muscles surrounding the airways tighten and contract as they try to keep the passageways open. Inhaled allergens or irritants like secondhand smoke and pollution act like sandpaper on the raw surfaces. You begin to cough and wheeze as you struggle to breathe. This is called bronchospasm.

Bronchospasm is the noisy part of asthma. Noisy asthma occurs when your airways are so inflamed they’re very sensitive. Exposure to the slightest irritation or allergen triggers bronchospasm – the twitching and sudden constriction of your airways creating the coughing, wheezing and shortness of breath that you can hear.

woman with curly hair holds her chest while having an asthma attack

What are common asthma symptoms and triggers?

The most common asthma symptoms are coughing, wheezing, chest tightness and shortness of breath. These symptoms occur when there’s inflammation in the airways, usually caused by triggers such as allergens, irritants and viruses. Asthma triggers are things in the environment that cause symptoms. They can vary from person to person. It is important to understand what makes your asthma worse.

Common asthma triggers include: pollen, mold, animal dander, dust mites, smoking or secondhand smoke, exercise, cold air, humidity and strong smells. People may also find their symptoms triggered by bacterial or viral respiratory infections such as the flu, a cold, sinus infection or pneumonia.

Infographic titled "Tips for Using Your Asthma Action Plan" with five tips: consult a doctor, keep plan accessible, maintain an electronic copy, check it regularly, and bring to appointments. Features illustrations of a doctor and nurse.

What is an Asthma Action Plan?

An Asthma Action Plan is a written personal asthma treatment plan. Your plan should spell out how to treat your asthma daily, what to do when symptoms get worse and how to manage situations such as exercise or when you have a cold or virus.

Girl Reaching For Asthma Inhaler Preventing Respiratory Depression Sitting On Couch At Home. Shallow Depth, Selective Focus

What is an asthma attack?

If your asthma symptoms suddenly worsen, you could be having an asthma attack. Asthma attacks are also referred to as asthma flare-ups, exacerbations, or episodes.

An asthma attack occurs when an allergen, irritant or virus causes the lungs to become inflamed. The muscles around the breathing tubes tighten or spasm. This narrows the airways and makes it harder to breathe. These signs indicate the need for immediate medical treatment. Make sure your Asthma Action Plan details steps to take to treat severe asthma attacks.

How do you stop an asthma attack?

Your doctor can help you develop an Asthma Action Plan that explains how to treat an asthma attack. It will detail your asthma medicines. You may need to use a quick-relief albuterol inhaler (also called a rescue inhaler). If your symptoms to not improve, it is a medical emergency and you should call 9-1-1 for help.

Learn about asthma medications and treatment so you know how to prevent and treat an asthma attack.

Asthma Questions & Answers (Q&As)

Asthma can look different in everyone, and if you’re a parent of a child with asthma it can also be scary. Here are some questions that are often asked, please email the editor if you have more questions.

You might think there would be less exposure to allergens and irritants in the bedroom at nighttime. Truth is, the bedroom can be full of potential allergens. There could be dust mites in the bedding, or maybe there’s a pet sleeping in the bedroom at night. Often people with asthma have increased issues at night.

If you experience disrupted sleep due to nighttime symptoms, or you are frequently using your quick-relief albuterol inhaler at night, it may mean that your asthma is getting worse. Schedule an appointment with your asthma specialist and ask to update your Asthma Action Plan.

Gestational asthma is asthma that occurs during pregnancy. Hormonal changes that occur during pregnancy can affect a woman’s existing asthma. Some women actually experience improved symptoms during pregnancy while others may have worsened symptoms. Maintaining disease control prior to and during pregnancy is essential to preventing complications. It’s important to note that pregnancy does not cause asthma.

There is no doubt that asthma tends to run in families. More than 100 genes have been found to be associated with asthma. Those genes are not a predictor of who will develop asthma and who won’t. Rather, genetics appears to play one part in who develops asthma. Environmental factors do as well.

People can inherit genes that may put them at greater risk for developing asthma. But genetics alone are not a sole predictor. The environment in which we live often plays a large role in asthma. When you see a family with multiple people with asthma, it may be a combination of genetics and the environment. Maybe they were already genetically predisposed, but perhaps living in an area with a lot of air pollution or residing in an older house with indoor mold exacerbated it. So the environment and exposure to allergens and irritants may play a role in the disease.

During an asthma episode or asthma attack, the airways become inflamed and swollen, and mucus production increases. The airways spasm to cause coughing, wheezing and shortness of breath. People may experience short rapid breathing and feel they can’t take in a deep breath.

Unfortunately, yes. Asthma is a life-threatening condition. In fact, more than 3,500 Americans die from asthma every year. Many of these deaths occur in people over the age of 65. Most asthma deaths are preventable. It is vital for everyone with asthma to carry a quick-relief inhaler to relieve symptoms in the event of an asthma attack.

People with asthma are not immunocompromised in the way most of us think, such as a person whose immune system is suppressed after undergoing chemotherapy. However, people with asthma are more prone to respiratory infections. Some may have a weakened immune system or reduced lung function due to asthma or another respiratory illness. It is important for people with asthma to be especially careful to prevent respiratory infections that may worsen symptoms. Getting the annual flu vaccines is a good way to start.

People with occupational asthma develop asthma as a result of their daily exposures through their occupation. It occurs primarily in adults. Some workplaces may have poor air quality due to presence of mold, a proximity to highways or ongoing construction. Other workplaces may use cleaning products that contain harmful irritants from chemicals. These can trigger asthma symptoms in some people.

The inflammation and the swelling cause airways to narrow and then spasm. This causes coughing, wheezing and shortness of breath.

Wheezing is a a high-pitched whistling sound during breathing. The sound is the result of air moving through the inflamed and swollen bronchial tubes. Sometimes wheezing is heard easily. Other times you need a stethoscope.

There is no specific diet for asthma patients, but there are certain foods that may reduce the risk of airway inflammation. People with asthma should focus on eating a healthy, well-balanced diet consisting of fresh fruit and vegetables. These foods, along with fish containing Omega 3 fatty acids, have been shown to have an anti-inflammatory effect. Foods with vitamin D may also help reduce the risk of asthma symptoms.

Asthma cannot be cured. It can be controlled. Work together with your healthcare provider to achieve asthma control. This can be done through medication and, if needed, lifestyle changes. If you have allergic asthma, consider allergen immunotherapy (also called allergy shots or tablets). Immunotherapy can help build your tolerance to an allergen, with the goal of reducing or even eliminating symptoms.

There is a lot you can do at home to make your home asthma friendly!

  • Quit smoking – until you or your family members quit smoking, make sure they only smoke outside
  • Avoid dust mites – use dust-proof covers on pillows and mattresses and wash bedding in hot water weekly.
  • Breathe healthy air – watch the air quality index daily. If air quality is poor, keep windows closed.
  • Keep it fresh – dust and vacuum regularly to avoid buildup of dust and other triggers.
  • Limit pets – skin, urine and saliva of pets can trigger allergies, so limit where pets can go inside. Keep them out of the bedroom.
  • Clean up food right away – don’t invite critters such as cockroaches by leaving food out.
  • Avoid sprays – sprays used to control pests can trigger asthma. Use baits or traps instead.
  • Keep mold at bay – mold is a major asthma trigger, so clean regularly to avoid buildup of moisture. Fix leaks quickly to prevent mold. Get rid of any moldy items such as carpets, insulation, or walls. Use fans to keep air circulating.

Asthma doctors, or asthma specialists, are allergists/immunologists or pulmonologists. These doctors have specialized medical education in the treatment of asthma, allergies and related diseases.

It is rare for children to outgrow asthma. Even if symptoms are well controlled for years, the disease often persists into adulthood. If symptoms diminish as a child grows, it could be the result of the child’s lungs or immune system adapting and improving over time. Or the child gradually learned to avoid asthma triggers, such as allergens. But it is rare for asthma to go away for good. Some adults have reported their asthma symptoms, first diagnosed in childhood, reappeared after many years.

People with moderate to severe asthma require strong medications to keep symptoms under control. These medications may include:

  • high-dose inhaled corticosteroids plus long-acting beta2-agonists and/or additional controller medications;
  • oral corticosteroids.

If moderate to severe asthma remains uncontrolled despite treatment and symptoms impact your ability to perform daily activities, then talk with your doctor about the next tier of medications: biologics.

Severe persistent asthma is the diagnosis when people experience symptoms at least twice a week and need to frequently use their quick-relief inhaler. They may also wake up at night one or more times per week with asthma symptoms. Severe persistent asthma may significantly impair a person’s daily life.

Reviewed by:
Bradley Chipps, MD, FACAAI, is a board-certified allergist and pediatric pulmonologist with Capital Allergy and Respiratory Disease Center in Sacramento, California. He earned his medical degree from University of Texas Medical Branch in Galveston in 1972. He is Past President of the American College of Allergy, Asthma and Immunology (ACAAI).