What Is Severe Asthma?
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Medically reviewed by Reza Samad, MD
Severe asthma is the term used for asthma that is difficult to treat and control. Asthma is a chronic disease that causes the airways—the tubes that carry air in and out of your lungs—to become inflamed and narrow, making breathing difficult.
People with severe asthma can take the highest dose of medications and follow their treatment plan but still experience asthma symptoms like shortness of breath, chronic cough, wheezing, chest tightness, and rapid breathing.
Between 5-10% of the 25 million people in the United States with asthma have severe asthma. With severe asthma, symptoms often occur day and night, leading to frequent absences from school or work and high rates of emergency department visits and hospitalizations.
Treatment of severe asthma focuses on controlling symptoms and usually includes a combination of medications and lifestyle modifications.
What Separates Severe Asthma From Other Types?
All asthma types involve airway inflammation and breathing difficulties. Severe asthma differs because it does not respond well to standard asthma treatments.
In most cases of asthma, quick-relief, and long-term controller medications effectively control airway inflammation and reduce the frequency and severity of symptoms. This is known as well-controlled asthma.
There's also uncontrolled asthma. This is when asthma symptoms occur frequently and often affect your activity levels and sleep. However, people with uncontrolled asthma can improve their symptoms by taking medications as prescribed or adjusting their treatment plan as needed.
Unlike uncontrolled asthma, severe asthma does not improve even when taking the highest dose of an inhaled corticosteroid along with a second controller medicine and/or an oral corticosteroid.
Types of Severe Asthma
There are two main types of severe asthma: type-2 inflammation and non-type-2 inflammation. The type you have depends on how you respond to certain treatments.
Type-2 inflammation includes allergic asthma and eosinophilic asthma. Allergic asthma is triggered by allergens you breathe in. Eosinophilic asthma is caused by high levels of white blood cells called eosinophils in the lungs' airways.
Non-type-2 inflammation includes non-eosinophilic asthma, which is airway inflammation without high levels of eosinophils.
Severe Asthma Symptoms
Symptoms of severe asthma are similar to those of other types of asthma, such as:
Shortness of breath
Coughing
Wheezing (whistling sound during breathing)
Chest tightness or pain
Difficulty breathing
But with severe asthma, symptoms tend to be more intense and occur more frequently. Severe asthma symptoms can be unpredictable, occur day or night, and last for prolonged periods. Because of this, severe asthma can seriously impact your quality of life and interfere with your ability to perform daily tasks.
For example, people with severe asthma are more likely to experience nighttime wakings from frequent coughing, wheezing, or shortness of breath disrupting sleep. This can lead to fatigue and daytime sleepiness. People with severe asthma also have higher rates of anxiety and depression than people without asthma.
People with severe asthma tend to experience more frequent asthma attacks (a sudden worsening of asthma symptoms).
What Causes Severe Asthma?
Chronic inflammation in the airways causes severe asthma. In many cases, the airways swell and narrow in response to breathing in triggers such as allergens like pet dander or airway irritants like cigarette smoke. Because airways are inflamed, it is harder for air to move in and out of the lungs.
Recent research shows that a type of airway inflammation called type-2 inflammation causes up to 70% of all asthma cases, including severe asthma. Type-2 inflammation is an overactive immune response that activates immune cells in response to a trigger. The immune cells release inflammatory substances, such as the proteins cytokines, and chemokines. This release causes airway inflammation and increases the risk of asthma attacks and reduced lung function.
Risk Factors
Certain factors increase your risk of severe asthma, including:
Genetics: People with one or both parents with type 2 inflammation-related asthma are four times more likely to develop asthma.
Sex: Men have higher rates of severe asthma than women.
Smoking: A history of smoking increases the risk of severe asthma.
How Is It Diagnosed?
If you are on the highest dose of asthma medications, follow your treatment plan, and have frequent and intense asthma symptoms for three to six months, your healthcare provider may suspect severe asthma.
After reviewing your medical history and current treatment plan and asking about your symptoms and their impact on your life, the provider may order testing to confirm the diagnosis. These tests may include:
Blood tests: These can identify and measure biomarkers associated with severe asthma, including the antibody immunoglobulin E (IgE) and eosinophils.
Sputum test: If your cough produces mucus, your healthcare provider may take a mucus (sputum) sample and send it to the lab to measure eosinophil and neutrophil levels. People with certain types of severe asthma have elevated levels of these white blood cells.
Spirometry: This test uses a tool to assess lung function by measuring how much air you can breathe in and out of your lungs and how quickly you can forcibly exhale air. People with severe asthma typically have significantly reduced lung function.
Fractional exhaled nitric oxide (FeNO) test: A FeNO test measures the amount of nitric oxide in your breath to determine how inflamed your airways are and how effectively corticosteroids control the inflammation.
Treatments for Severe Asthma
The treatment goals for severe asthma are reducing airway inflammation, controlling symptoms, and improving lung function. Your healthcare provider will work with you to develop a treatment plan based on your type of severe asthma. The plan will likely include medications and lifestyle changes.
Inhaled or Oral Medications
Medications are the cornerstone of severe asthma treatment. Your healthcare provider may prescribe any of the following:
Inhaled corticosteroids: Inhalers can deliver strong anti-inflammatory drugs called corticosteroids directly into the airways when you inhale. Corticosteroids can reduce inflammation and mucus production and improve lung function. Most people with severe asthma must take inhaled corticosteroids daily. People with non-type-2 inflammation, such as non-eosinophilic asthma, don't usually respond well to inhaled corticosteroids.
Combination medications: Some inhaled medications contain corticosteroids and a long-acting beta2-agonist (LABA) or long-acting muscarinic antagonist (LAMA). Taken daily, combination medications reduce airway inflammation to relieve symptoms and improve lung function.
Bronchodilators: Also known as quick-relief medications, you breathe these drugs (beta2-agnostics and anticholinergics) in through an inhaler to quickly open your airways and relieve worsening asthma symptoms.
Oral corticosteroids: These strong anti-inflammatory tablet medications are taken by mouth and help reduce inflammation and control symptoms. They're usually taken on a short-term basis, though some people with severe asthma who experience frequent asthma attacks may need them long-term.
Biologics
Biologics are a newer class of medications that are administered under the skin or through a vein bi-weekly, monthly, or bi-monthly.
Biologics target specific aspects of the immune cells and pathways involved in type-2 inflammation. The medications inhibit inflammatory substances and interrupt the inflammatory process to reduce inflammation, reduce asthma symptom flare-ups, and improve lung function.
The type of biologic drug your healthcare provider prescribes will depend on the specific inflammatory substances associated with your type of severe asthma. Types of biologics that treat severe asthma associated with type-2 inflammation include:
Xolair (omalizumab): Blocks the antibody IgE in people with allergic airway inflammation
Nucala (mepolizumab): Targets interleukin-5 (IL-5), an inflammatory cytokine associated with eosinophil production, to reduce eosinophil counts in the blood
Dupixent (dupilumab): Blocks interleukin 4 (IL-4) and interleukin 13 (IL-13), cytokines that play a role in airway inflammation, to reduce eosinophil counts
Fasenra (benralizumab): Targets IL-5 to prevent eosinophil activation and reduce airway inflammation
Cinqair (reslizumab): Targets IL-5 to decrease eosinophils and control airway inflammation
Bronchial Thermoplasty
Bronchial thermoplasty is a procedure that uses heat to reduce excess smooth muscle tissue in the airways. The goal is to reduce airway constriction and asthma symptoms.
Before the procedure, you will receive sedative medication or anesthesia to ensure you don't feel pain or discomfort.
During the procedure, your healthcare provider will insert an endoscope (a long, flexible tube) through your mouth and into the airways to deliver heat to targeted areas of the airways. You may need to stay in the hospital for several hours or overnight following the procedure.
While you may experience worsening asthma symptoms for a week or two after the procedure, most people who undergo bronchial thermoplasty report a reduction in the severity and frequency of asthma symptoms and attacks.
Lifestyle Changes
If you smoke, quitting can help improve your severe asthma. If you don't smoke but are around people who do, try to avoid the secondhand smoke.
Maintaining a well-balanced diet and exercising regularly may also help improve your asthma. Avoiding environmental triggers like pollen can also reduce your risk of asthma symptoms.
Prevention
While you can't prevent severe asthma, you can lower your risk of severe asthma attacks by doing the following:
Stick to your treatment plan: Take all medications as prescribed to keep airway inflammation under control.
Identify and avoid triggers: Take note of what triggers worsen asthma symptoms and avoid them to reduce your risk of asthma attacks.
Have an asthma action plan: Develop an action plan with your healthcare provider that outlines how to manage early asthma attack warning signs and when to take quick-relief medications to lower the risk of symptoms escalating into severe attacks.
Get vaccinated: Stay up-to-date on influenza, pneumonia, and COVID-19 vaccinations to help prevent respiratory infections that can trigger asthma attacks.
Manage stress: Stress and strong emotions can worsen asthma symptoms, so managing and minimizing stress may help prevent severe asthma attacks.
Related Conditions
People with severe asthma often have other conditions that can worsen or trigger asthma symptoms. Conditions related to severe asthma include:
Allergic rhinitis (hay fever): This condition causes watery eyes, itchy nose, sneezing, and congestion in response to an allergen like pollen or dust mites. Up to 80% of people with severe asthma have allergic rhinitis.
Sinusitis: Inflammation of the sinuses, the air-filled cavities around the face, causes mucus build-up in the sinuses. This can worsen asthma symptoms and increase the risk of asthma attacks.
Gastroesophageal reflux disease (GERD): GERD causes stomach acid to back up into the esophagus, irritating the airways and worsening asthma symptoms.
Chronic rhinosinusitis with nasal polyps: Chronic inflammation in the sinuses (lasting 12 weeks or longer) accompanied by nasal polyps (soft growths in the nasal lining) often occurs with severe asthma.
Atopic dermatitis: This chronic inflammatory skin condition that causes intensely itchy skin is more common in people with severe asthma, particularly those with type-2 inflammation, due to elevated IgE levels and shared genetic factors.
Obstructive sleep apnea: The sleep disorder causes frequent pauses in breathing during sleep and is associated with poor asthma control, frequent nighttime asthma symptoms, and worsened asthma symptoms.
Living With Severe Asthma
Severe asthma can affect every aspect of daily life. Everyday occurrences like climbing stairs or laughing with friends may suddenly make breathing labored.
While living with severe asthma requires careful planning and lifestyle modifications to avoid triggers and control symptoms, the condition doesn’t have to define your life. Following your treatment plan and working closely with your healthcare provider can help get severe asthma under control and reduce its impact on your life.
Joining a support group for people with similar experiences can be valuable for managing the challenges of this diagnosis and feeling less alone. Talk to your healthcare provider if you are struggling with symptom management or the emotional aspects of severe asthma. They can provide the guidance and resources needed to help you cope.
Frequently Asked Questions
Is severe asthma life-threatening?
Severe asthma can be life-threatening if left untreated or if you experience a severe asthma attack and do not receive prompt medical treatment. With proper treatment and management, people with severe asthma can lead active and fulfilling lives.
How long do people with severe asthma live?
There is no set life expectancy for people with severe asthma, but most people with asthma can expect a near-average lifespan. A 2016 study found that asthma may shorten life expectancy by 3.3 years, but the risk of death is higher in people with uncontrolled asthma who don't take their medications as prescribed or don't seek medical attention for severe symptoms.
What happens if severe asthma is left untreated?
Untreated severe asthma can lead to permanent airway damage called airway remodeling. Frequent asthma attacks or uncontrolled symptoms can cause the airways to become thickened and scarred over time, making breathing harder and worsening symptoms.
Following your treatment plan and making lifestyle modifications are essential for preventing complications.
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