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What Causes Asthma? The 6 Most Common Causes


Understanding what causes asthma can help you better manage its causes and triggers. Whether you, your child or another loved one has asthma, you can feel more in control by knowing your options for reducing asthma symptoms and managing its underlying causes.

What is asthma?

Asthma is a chronic condition that causes swelling and inflammation in the airway tissues. This leads to a narrowing of your airways, making it more difficult to breathe, according to the Asthma and Allergy Foundation of America (AAFA).

About 1 in 13 people in the United States have asthma. It affects people who are seniors, low-income, Hispanic, Black and Native Americans more than other groups, and can start either in childhood or adulthood.

The symptoms of asthma include wheezing, coughing, shortness of breath and chest tightening. Different people have different triggers for these symptoms.

What are the causes of asthma?

Figuring out what causes asthma can be tricky because there are several reasons why it develops.

According to the American Lung Association (ALA) and the AAFA, the main causes of asthma include:

  • Allergies
  • Obesity
  • Smoking
  • Air pollution
  • Health conditions
  • Family history of asthma

Here, you can learn about each cause, plus some ways to manage them so that asthma isn’t triggered as easily.


Certain substances can cause you to develop allergic asthma. The AAFA says the most common include:

  • Dust mites
  • Pet dander
  • Mold
  • Pollen
  • Cockroaches
  • Rodents

In allergy-induced asthma, the immune system releases a certain type of antibody called immunoglobulin E (IgE). According to Cleveland Clinic immunologist Dr. Ronald Purcell, this immune response typically causes you to experience wheezing, sneezing and shortness of breath — all at the same time.

“The goal is to manage your condition so that it never limits the activities you love,” he explained in a recent Cleveland Clinic article.

To do this, Purcell recommended getting an allergy test to identify your specific triggers, changing clothes and showering after being outdoors, and using a HEPA filter in your home to reduce allergens.


The ALA explains that obese people have a higher risk of developing asthma than people of normal weight, possibly because obesity causes inflammation that can limit lung function.

People with a body mass index of 30 or greater are particularly susceptible to developing obesity-related asthma, according to the U.S. Centers for Disease Control and Prevention. Since it’s not as responsive to medications as other types of asthma, try walking or some other form of exercise every day to help reduce symptoms.


Because smoke causes inflammation, irritation and the build-up of mucus in the lungs, it can trigger asthma. The ALA notes that cigarette smoke may even destroy lung tissue. Unfortunately, 18% of American adults with asthma smoke, compared to just 13.6% without asthma.

Though quitting smoking can be a challenge, resources like the Lung HelpLine and the Freedom from Smoking® program are designed to help you break the habit.

Air pollutants

“Chronic exposure to pollution is very insidious because people don’t tend to realize the effect that these pollutants are having on their health over time,” pulmonologist Dr. Neha Solanki said in a recent Cleveland Clinic article.

According to the AAFA, air pollutants like dust, ozone and gases can get into your lungs and cause an interruption of normal lung functioning, making it difficult to breathe. Secondhand smoke can also cause asthma, as can other irritants in the air such as household cleaners, pesticides and air fresheners.

For indoor air pollutants, it’s best to find products that don’t trigger an asthma flare-up.

Health conditions

Several types of infections and health conditions can cause or worsen asthma, according to the AAFA, such as:

  • Viral infections of the airways, especially during childhood
  • Chronic obstructive pulmonary disease (COPD)
  • Gastroesophageal reflux disease (GERD)
  • Obstructive sleep apnea
  • Nasal polyps
  • Food allergies
  • Allergic bronchopulmonary aspergillosis (ABPA)
  • Pregnancy
Family history

“We know that our genetics can predispose some of us to have an allergy,” allergist Dr. Lily Pien noted in a recent Cleveland Clinic article.

In fact, people who have at least one parent with asthma are three to six times more likely to develop the condition than those who have no parents with the condition, according to the ALA.

Meanwhile, a cross-sectional survey of nearly 60,000 schoolchildren across China published recently in the journal Frontiers in Pediatrics revealed that having grandparents with the condition also increased kids’ risk of developing the condition.

If you’d like to better understand what causes asthma and how to manage it, the ALA and the AAFA each offer free, self-paced asthma care basics classes.