Multiple Phenotypes of Asthma Can Co-exist
Quick survey, who knows their phenotype? I am joking, this isn’t a quiz or a test but more a sign of where things are headed. You may have heard a lot of the discussion of precision medicine.
Today’s million dollar question: can multiple asthma phenotypes co-exist?
The answer to this question that was posed at an asthma conference is, YES! If a patient has identifying characteristics in multiple phenotypes, it is possible for them to have multiple phenotypes at the same time. Asthmatics are complex, and they can have multiple phenotypes. These multiple phenotypes can lead to a combined or prioritized strategy for treatment.
To recap, phenotypes are essentially a subgroup of asthma characteristics. Most of these characteristics are identified by their biological/physiological and biochemical processes. These processes also help guide treatment and are one of the key factors in the development of new medications to treat asthma.
Different asthma phenotypes
A selection of phenotypes includes:
Eosinophilic with high NO (nitric oxide levels): I know that many a fellow asthmatic is having FeNO or Nitric Oxide testing done in their doctor's office. This test was developed as a potential biomarker for:
Neutrophilic “infective, hypersecretory”: This is related to underlying causes of bronchiectasis. Bronchiectasis relates to the damage of our cilia which is responsible for getting rid of dirt and mucous in our airways. Airways widen and stretch out and form pockets in which dirt and mucous get stuck.1
Unstable (dysfunctional, brittle): This looks at maximizing bronchodilator therapies. In some patients, bronchial thermoplasty has been thought to be helpful.
Fungal (severe asthma with fungal sensitization) and ABPA (allergic bronchopulmonary aspergillosis): Fungal infections found in the airways has been linked to antifungal therapy.
Obstructive phenotype: This is connected to positive responses to long-acting anti-cholinergic “titoproium” therapies.
Severe allergic asthma: This has been linked to the effectiveness of biologic allergic therapies such as omalizumab.
Starting with an accurate diagnosis
All of the linkages to medication would not be possible without first identifying what is driving our asthma. I think that is one of the hardest parts of diagnosis, especially for complex, severe asthma. Figuring out what works is a lot of the battle. Under the premise of multiple phenotypes co-existing, it can be especially challenging for our clinicians to accurately determine where to begin.
With new biologics on the horizon, options are expanding beyond puffers and prednisone. Hooray!
I can’t stress enough that it is important that you have had an accurate diagnosis and that your phenotype is determined before these techniques are deployed. Often our docs may have our phenotypes identified but have not shared that information with us. That is a discussion for another day. However, it is always worth investigating while you are on a particular treatment and how it relates to your disease. I know that it has me immensely thinking about my disease differently and why I am on the particular regimen.
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