New Classification System for Chronic Rhinosinusitis Proposed

By Marilynn Larkin

July 16, 2020

NEW YORK (Reuters Health) - A new classification system for chronic rhinosinusitis (CRS) separates the condition into primary and secondary disease, as well as localized and diffuse, based on anatomical distribution.

A report online July 9 in JAMA Otolaryngology-Head and Neck Surgery offers details on the classification system, first published in March along with related research and documentation in the European Position Paper on Rhinosinusitis and Nasal Polyps 2020 (

"The prior description of chronic sinusitis as either disease with or without polyps is no longer adequate to characterize the patient's disease," Dr. Jessica Grayson of the University of Alabama at Birmingham told Reuters Health by email. "This suggestion of different phenotypes of upper airway disease has already been discussed in pulmonary pathology and studies. Therefore, the extrapolation to the upper airway was a natural progression of our knowledge."

The new classification system proposes that the functional anatomical compartments involved in CRS create the first level of separation into local or diffuse disease. These compartments are usually unilateral or bilateral.

Diffuse does not mean "pansinusitis," only that the disease is not confined to a known functional anatomical unit, according to the authors. The classification also takes into account whether local anatomical factors are associated with pathogenesis.

Next, the classification system separates the inflammatory endotype dominance into a type 2 skewed inflammation, which has both causal and treatment implications, or non-type 2 CRS. Non-type 2 CRS encompasses everything that is not yet known about inflammation and may change over time.

The authors state, "The proposed classification has been left intentionally simple (local or diffuse and type 2 or non-type 2) to give it the flexibility to incorporate future research and allow phenotypes to be defined. The proposal allows for current therapies, from balloons to macrolides to surgery and biologics, to be more appropriately directed."

Dr. Grayson noted, "While this classification system is not meant to be set in stone, it is the beginning of a discussion about how to best classify disease to get the best outcomes. As we learn more about the immunological processes of these diseases, this will continue to change, as it should."

"Improvement in these classifications will allow us quicker appropriate management for patients to get maximum benefit, as well as allow us to analyze apples to apples in research and clear the muddy water of the all-encompassing term, 'chronic rhinosinusitis,'" she said. "Future studies on endotyping which can help in the phenotypic classification of these diseases are underway."

Dr. Jonathan Overdevest, assistant professor of otolaryngology-head and neck surgery at Columbia University Medical Center in New York City, commented in an email to Reuters Health, "Most experts agree that traditional methods of differentiating patient groups based on phenotypes - the presence or absence of physical traits like polyps - limits our ability to more accurately treat the underlying mechanisms of the disease. Enter endotyping, which looks to identify the molecular pathways involved in a particular case of sinusitis. The classification system proposed by the authors seeks to harmonize these subtyping methods into a user-friendly format."

"Many of the features involved in this system are factored into our conventional analysis of a patient's disease - distribution, severity, mechanism, and patient-specific presentation," he said. "This system...establishes a roadmap to more consciously identify these discrete factors and utilize them in a stepwise fashion".

"While we continue to integrate the molecular biology of sinusitis into daily practice, we will need expanded classification systems as well as identification of biomarkers that link phenotypes to endotypes to enhance our precision in selecting targeted treatments," he concluded.

SOURCE: JAMA Otolaryngology-Head and Neck Surgery, online July 9, 2020.