Asthma affects about 9.4% of children and 7.7% of adults in the United States.
In many cases, asthma is a lifelong condition that a person can control by taking medications and avoiding triggers that trigger asthma attacks.
Although childhood asthma and adult-onset asthma are similar, symptoms can vary in severity. Learn more about the difference between adult-onset and childhood asthma here.
Certain triggers in the environment can also worsen asthma symptoms and trigger an asthma attack.
Keep reading to learn more about the different types of asthma, including symptoms and treatment options.
Allergic asthma is the most common type, affecting about 60 percent of people in the United States.
8 out of 10 people with allergic asthma will also have another allergic condition, such as eczema, allergic rhinitis, or food allergies.
Certain allergens in the environment can trigger allergic asthma. Some common allergens include:
- pet dander
- mold spores
- foods such as milk, eggs, and certain nuts
- dust mites, cockroaches, and cockroach feces
- irritants in the air, such as tobacco smoke and automobile and chemical fumes
- heavily fragranced products, such as perfumes
Nonallergic, or intrinsic, asthma does not require an allergen to trigger an attack.
It is less common than allergic asthma, accounting for about 10-33% of all asthma cases. It is more likely to appear in adolescence and affects women more than men.
Experts believe that non-allergic asthma is caused by genetic and environmental factors.
For example, symptoms may develop when a person experiences:
- irritants in the air, such as smoke
- respiratory infections, such as a cold, flu, or sinus infection
In seasonal asthma, symptoms flare up under certain conditions or at certain times of the year.
For example, a person with seasonal asthma may notice that symptoms are worse, or only present, during:
- Hay fever season, when pollen levels are highest.
- Cold or hot weather, thunderstorms and sudden changes in temperature
- Days when air pollution is worse, such as cold days
- During the winter months, when there are more cold and flu viruses around.
In many ways, seasonal asthma is similar to allergic asthma. In fact, people may use both terms to describe asthma attacks that occur during pollen season.
People with occupational asthma may find that their symptoms worsen while working, or improve with time off work.
In fact, 15% of asthma cases in the US can be attributed to work-related exposure to paint chemicals, aerosols, pesticides, or other harmful substances.
How long it takes for symptoms to appear depends on the level of exposure to these and other substances. Some people may have an asthma attack within 24 hours of exposure. In others, it may take months, or even years, for any symptoms to develop.
Exercise-induced asthma occurs when symptoms flare up during or shortly after exercise or other forms of strenuous activity. This can happen about 5-20 minutes after exercise.
While it’s common to experience shortness of breath after exercise, exercise-induced asthma can also cause coughing, wheezing, and chest pain, ranging from mild to severe.
About 90% of people with asthma also experience exercise-induced asthma, in most cases a mild form that responds well to treatment.
The following factors can also worsen exercise-induced asthma symptoms:
- chlorinated pools
- exposure to polluted air while running or cycling outside
- cold, dry air while ice skating or playing hockey
- warm, humid air while doing hot yoga
Severe asthma, or refractory asthma, affects 4% of all adults with asthma.
Experts consider asthma severe when symptoms do not improve with standard medications. People with severe asthma are more likely to:
- People with mild to moderate asthma tend to have more asthma attacks.
- Spend more time in hospital as a result of your asthma.
- Take long-term steroid pills.
Symptoms of severe asthma are similar to those of mild to moderate asthma, but can be much more severe. They can sometimes be fatal.