Clinicians Urged to Adopt the New and Improved Classification System for Rosacea

With the new phenotype-based diagnostic system, it is now possible to address the signs and symptoms of rosacea in a more targeted manner.


Figure. The new standard system establishes that the presence of 1 of 2 phenotypes is considered diagnostic of rosacea. 

Since the appearance of the original standard classification of rosacea in 2002, significant new insights into rosacea’s pathogenesis and pathophysiology have emerged, and the disorder has received wider recognition among both physicians and patients. The National Rosacea Society (NRS) recently published an update to the classification system.1 

This new classification system was developed by a consensus committee and reviewed by a panel of 28 rosacea experts. It takes advantage of recent advances in scientific understanding of rosacea and encourages clinicians to consider the full range of signs and symptoms. The intent of this is to provide more precisely tailored treatment of the specific characteristics and severity found in each individual patient as well as to further advance understanding of this important disease.

The New System

While the original standard classification of rosacea identified the most common groupings of signs and symptoms morphologically as subtypes, the new system is based on the individual characteristics, called phenotypes, that may result from the underlying disease process. 

The new standard system establishes that the presence of 1 of 2 phenotypes—persistent centrofacial erythema or, less commonly, phymatous changes, often around the nose—is considered diagnostic of rosacea. Additional major phenotypes are also recognized; these often appear with the diagnostic features such as papules and pustules, flushing, telangiectasia, and certain ocular manifestations. The presence of 2 or more major phenotypes independent of the diagnostic features can also be considered diagnostic of rosacea. Secondary phenotypes, which must appear with one or more diagnostic or major phenotypes, include burning or stinging, edema, and dry appearance.

Signs suggestive of ocular rosacea include telangiectases on the eyelid margin and bloodshot eyes, as well as inflammation and growth of fibrous tissue on the eye. Burning, stinging, light sensitivity, and the sensation of a foreign object may also occur, as well as conjunctivitis, blepharitis, chalazia, and crusty accumulations at the base of the eyelashes, in addition to others.

Multivariate Disease Process

Recent studies have shown that a consistent multivariate disease process underlies the various clinical manifestations of rosacea. The initial erythema appears to be the start of an inflammatory continuum initiated by neurovascular dysregulation and the innate immune system, including the discovery of irregularities of key components known as cathelicidins. Research has further demonstrated that a marked increase in mast cells, located at the interface between the nervous system and vascular system, is a common link in all major presentations of the disorder. Other studies have documented a possible genetic component, as well as the potential role of the human microbiome, including Demodex mites and certain bacteria.

Comorbidities and Other Factors

The consensus committee also emphasized that clinicians should factor the psychosocial effects of rosacea on their patients into their treatment, as multiple patient surveys have documented rosacea’s substantial adverse impact on emotional, social, and occupational well-being. In surveys conducted by the NRS, more than 90% of rosacea patients said the disorder had lowered their self-confidence and self-esteem, and 41% reported that it had caused them to avoid public contact or cancel social engagements. Eighty-eight percent of rosacea patients with severe symptoms said the disorder had adversely affected their professional interactions and 51% said they had even missed work because of their condition.

The consensus committee additionally published an accompanying commentary on comorbidities, summarizing the many recent studies that have found associations between rosacea and an increased risk for a growing number of potentially serious systemic disorders.2 These include cardiovascular disease, gastrointestinal disease, neurological and autoimmune diseases, and certain cancers. Although causal relationships have not been determined, the committee noted these findings may substantially increase the clinical significance of rosacea as evidence that the disorder may be an outcome of systemic inflammation continues to mount.

In addition to comorbidities, they noted that recent evidence suggests clinicians may expect to find rosacea in individuals with darker skin types and may use the updated standard criteria to determine its presence in various ethnicities. 

Future Outlook

As with the original classification of rosacea, the updated standard system is considered provisional and may require modification as knowledge of the disease process continues to advance, and as the relevance and applicability of the new system are tested by researchers and in clinical practice. Physicians are encouraged to immediately implement the new, more specific, and research-based guide to the diagnosis and assessment of rosacea.

Beyond the advances in understanding of the pathophysiology of rosacea, clinicians today have at their disposal a growing range of therapeutic options. With the new phenotype-based diagnostic system, it is now possible to address the signs and symptoms of rosacea in a more targeted manner, tailored for each individual patient. 


Dr Gallo is a member of the National Rosacea Society Medical Advisory Board. He is a distinguished professor and founding chair for the department of dermatology at the University of California, San Diego. His research focuses on the role of the innate immune system in skin health and disease, focusing on antimicrobial peptides and aspects of the basic functions of the skin immune system. Dr Gallo’s clinical practice is located at the VA Medical Center in La Jolla.



1. Gallo RL, Granstein RD, Kang S, et al. Standard classification and pathophysiology of rosacea: The 2017 update by the National Rosacea Society Expert Committee. J Am Acad Dermatol. 2018;78(1):148-155. 

2. Gallo RL, Granstein RD, Kang S, et al. Rosacea comorbidities and future research: The 2017 update by the National Rosacea Society Expert Committee. J Am Acad Dermatol. 2018;78(1):167-170.