Asthma is a chronic lung condition that inflames and narrows the large and small airways of the lungs, making it difficult to breathe. When you breathe, air enters the lungs through the large airways before moving into the small airways. While inflammation is usually a defense mechanism for the body, it can be harmful if it occurs at the wrong time or lingers. When the inner linings of the small and large airways become inflamed, they can become constricted and blocked with mucus. As a result, there is less room for air to move through.

Asthma severity can be classified by four levels:

Asthma is not one size fits all. The severity of asthma varies from person to person. While some people may experience occasional mild asthma symptoms that respond well to a "quick-relief" inhaler, others with more persistent asthma may need daily maintenance treatments to control their symptoms.

Your doctor will determine the severity of your asthma based on a number of factors, including how often you have symptoms or use your rescue inhaler, how much trouble you have with daily activities due to asthma, and the results of a lung function test called spirometry. Spirometry measures how much and how fast you can inhale and exhale. Spirometry results are given as a percentage of FEV1, and a higher percentage indicates better lung function.

Regardless of the severity of your asthma, it’s important to remember that asthma inflammation is always present, whether you or your child is experiencing symptoms or not.

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  Intermittent Asthma Mild Persistent Asthma Moderate Persistent Asthma Severe Persistent Asthma
Daytime asthma symptoms <2 Days/Week 2 + Days/Week Daily Throughout the day
Waking up due to asthma <2 Nights/Month 3-4 Nights/Month 1 + Nights/Week Every Night
Needing a rescue inhaler <2 Days/Week 2 + Days/Week Daily Multiple times per Day
Trouble with daily activities due to asthma None Minor Moderate Excessively
Lung function tests Normal (100%) FEV1 80-100% of FEV1 60-80% of FEV1 <60% of FEV1

Incidence of Asthma

According to the Centers for Disease Control (CDC), asthma affects approximately 25 million Americans and is one of the most common long-term diseases of children. However, many adults suffer from asthma too.

Genetics play a role in developing asthma. When you talk with your doctor, he or she may ask if anyone else in your family suffers from asthma. A child is more likely to be diagnosed with asthma if one or both parents have asthma.

Unfortunately, there is no known cure for asthma, but asthma can be controlled with regular monitoring, proper treatment and by avoiding "asthma triggers." It's important to work closely with your doctor to regularly assess control and determine appropriate treatment options, as symptoms and disease severity vary for each person.