People with asthma usually have recurring symptoms and flares when symptoms worsen, but that does not always mean they have severe asthma. Only about 5 to 10 percent of people with asthma have a severe form of the disease.
Severe asthma is categorized into two main types, based on a person’s response to treatment:
- Type-2 inflammation
- These types respond to treatment with inhaled corticosteroids and IgE (biomarker immunoglobulin E)-directed therapy or other biologics
- Allergic asthma
- Eosinophilic asthma (E-asthma)
- Characterized by an increase in a type of white blood cell that helps fight disease and infections (eosinophils)
- Increased eosinophils may be due to allergic reactions, parasitic disease, or a reaction to a medication
- In some people, high eosinophil levels can result in inflammation of the airways and cause asthma symptoms
- Non-type-2 inflammation
- Patients generally do not respond well to inhaled corticosteroids
- Non-eosinophilic asthma
- Includes neutrophilic, smooth-muscle mediated, and mixed cells
- Few to no eosinophils appear in test results
What Are Symptoms of Asthma?
Asthma symptoms may:
- Come and go over time
- Start or worsen with viral infections, such as a cold
- Worsen at in the morning or at night
Symptoms of mild, moderate, and severe asthma may include:
- Difficulty breathing
- Shortness of breath
- Chest tightness
- Coughing, especially at night or early morning, during exercise, or when laughing
- Asthma attacks
- Episodes of significantly worsening symptoms that require a change in usual treatment
- May come on either gradually or suddenly and can be life-threatening
What Causes Severe Asthma?
The cause of asthma is unknown, but it usually results from a strong immune system response to a substance in the lungs.
Common triggers for asthma symptoms include:
- Allergies (such as pollen, ragweed, dust mites, mold, or animal dander)
- Irritants in the air (such as smoke, strong odors, chemical fumes)
- Gastroesophageal reflux disease (GERD)
- Extreme weather conditions
- Cold air
- Illness, particularly respiratory illness or the flu
- Strong emotions that can affect normal breathing patterns, such as laughing, crying, or shouting
- Certain medications
- Some foods
How Is Severe Asthma Diagnosed?
Severe asthma is diagnosed with a patient history and a physical exam, which includes the doctor listening to a patient’s breathing and checking for allergic skin conditions.
Tests used to help diagnose asthma or rule out other causes for symptoms include:
- Pulmonary function tests
- Bronchoprovocation tests
- Peak expiratory flow (PEF)
- Fractional exhaled nitric oxide (FeNO) tests
- Provocation (trigger) tests
- Exercise challenge
- Irritant challenge
- Methacholine challenge
- Allergy skin or blood tests, in patients who have a history of allergies
- Immunoglobulin E (IgE)
Diagnosing asthma in children younger than 6 can be difficult, since young children are usually unable to perform a pulmonary function test such as spirometry. Asthma medicines may be tried for a few months to see how the child responds.
What Is the Treatment for Severe Asthma?
Asthma is usually treated with quick-relief and long-term control medicines. Allergy shots (immunotherapy) may also be helpful.
Quick-relief medications are bronchodilators that expand the airways, and are taken at the first sign of asthma symptoms for immediate relief:
- Short-acting inhaled beta2-agonists (inhalers)
Long-term asthma control medications are taken daily to prevent symptoms and asthma attacks and include:
- Inhaled corticosteroids
- Antileukotrienes or leukotriene modifiers
- Long-acting inhaled beta2-agonists (usually combined with an inhaled corticosteroid)
Patients with severe asthma often use the highest dose of inhaled corticosteroids plus a second controller and/or oral corticosteroids but despite use of high dose medicines, asthma may still be uncontrolled.
In severe asthma, when traditional treatments do not work well enough other therapies may be used, such as:
- Oral corticosteroids
- Immunotherapy, useful when asthma is triggered by an allergy
- Allergy shots (subcutaneous immunotherapy [SCIT])
- Sublingual (under the tongue) tablets or drops (sublingual immunotherapy [SLIT])
- Macrolide antibiotics to help the body fight infection and control the number of white blood cells (neutrophils) found in the airways
- Behavior and lifestyle changes
- Bronchial thermoplasty (BT)
- A procedure that uses radio frequency energy to apply mild heat to the smooth muscle tissue in the airway, reducing the amount of smooth muscle tissue, causing less airway constriction and reducing flareups
- Limited to patients whose severe asthma does not respond well to inhaled corticosteroids and/or long-acting bronchodilator medications and who also use oral corticosteroids more than twice a year to manage asthma attacks or take an oral corticosteroid for daily maintenance
- Only available to adults and not used in patients with other health conditions