Asthma Subgroups: Severe Asthma
One of the most recently defined asthma subgroups is severe asthma. It was first defined about 20 years ago. This was when physicians recognized 5-10% of asthmatics did not respond to corticosteroids. They continued to have difficulty controlling asthma despite the best treatment. Here’s what researchers currently know.1
What is difficult-to-treat asthma?
It’s asthma that is difficult to control. It could be due to…
- Misdiagnosis. The person is being treated for asthma but does not have asthma. Various diseases mimic asthma (like COPD or obesity) but do not respond to asthma medications. So, the road to improved symptoms in these cases may begin with a proper diagnosis.1-5
- Poor patient compliance. The person has asthma but isn't adhering to a treatment program. They may be forgetting to take their medicine. They may not be taking it right. The road to better asthma control may be education.1-5
- Severe asthma. I will describe this in a moment. First, a misdiagnosis and poor patient compliance must be ruled out. Once that's done, a diagnosis of severe asthma can be made.1-5
What is severe asthma?
How to define severe asthma was open to debate until 2014. This was when a joint conference of the American Thoracic Society and the European Respiratory Society defined it as:
Severe asthma refers to asthma that:3
- "...requires treatment with high-dose inhaled corticosteroids (ICS) plus a second controller during the full previous year and/or systemic corticosteroids (CS) during 50% or more of the previous year to prevent symptoms from becoming “uncontrolled,” or...
- ...remains “uncontrolled“ despite this therapy."
What is refractory or steroid-refractory asthma?
According to Merriam-Webster, refractory means “resistant to treatment.” So, refractory asthma refers to asthma that is resistant to treatment. Steroid refractory asthma refers to asthma that is resistant to corticosteroids. Some severe asthmatics have this.
What causes steroid-refractory asthma?
Airway remodeling is a common cause. This is where airway walls are thicker than normal and not responsive to treatment. Asthmatics who present with neutrophilic airway inflammation may cause it. This type of inflammation may come with a diagnosis of asthma/COPD overlap syndrome. It may include premenopausal or occupational asthma.
Treating refractory asthma
Traditional asthma medicines like inhaled corticosteroids are usually tried. The highest doses are usually needed. Non-traditional, or second-line, asthma treatment may is often used. This may include medications like Singulair or Xolair. It may include using COPD medicine like Spiriva. It may include trying old asthma medicine like theophylline. It may include using unique treatments like macrolides, antifungal agents. It may include a surgery called bronchial thermoplasty.1,3-6
What else might cause severe asthma?
Late-onset asthma tends to be more severe.2 Late-onset subgroups include eosinophilic and aspirin associated asthma. It may also include allergic bronchopulmonary aspergillosis or Churg Strauss Syndrome.
About 19-34% of severe asthma cases involve asthma that exists with another co-morbidity.7 Examples include allergies, rhinitis, COPD, GERD, stress, or anxiety. When this is the case, controlling one means controlling the other. Sometimes, even allergic asthma can become severe. This is because it consists of both allergies and asthma. In such instances, severe asthma may be diagnosed in childhood.2,8
How is a diagnosis of severe asthma helpful?
After diagnosing severe asthma, a quest can begin to determine why it's severe. Is it because of your subgroup? Is it because you have more than one subgroup? The answers to these subgroups can lead you and your doctor to a treatment regimen that works for you. This is all an attempt to help all asthmatics reach ideal asthma control.
What has your experience with Singulair been like?