New Standard Classification and Pathophysiology of Rosacea Published
“There has been an explosion of research on rosacea since the first standard classification system appeared in 2002, and that has resulted in a much deeper scientific understanding of this common but once little-known disorder,” said Dr. Richard Gallo, chairman of dermatology, University of California-San Diego and chairman of the NRS consensus committee.
“Growing knowledge of rosacea’s pathophysiology has established that a consistent multivariate disease process underlies its various clinical manifestations, which may also potentially be associated with other systemic disorders,” he said.
Although the cause of rosacea remains unknown, researchers have now identified major elements of the disease process that may lead to significant advances in its treatment. Recent studies have shown that the initial redness is likely to be the start of an inflammatory continuum initiated by a combination of neurovascular dysregulation and the innate immune system. The role of the innate immune system in rosacea has been the focus of groundbreaking studies funded by the NRS, including the discovery of irregularities of key components known as cathelicidins.
Further research has now 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.
While the original classification system designated the most common groupings of primary and secondary features as subtypes, the committee noted that because rosacea appears to encompass a consistent inflammatory continuum, it now seems appropriate to focus on the individual characteristics, called phenotypes, that may result from this disease process. Observing the respective phenotypes in clinical practice will also encourage consideration of the full range of potential signs and symptoms that may occur in any individual patient, and assessment of severity and the selection of treatment may be more precisely tailored to each person.
According to the new system, the presence of 1 of 2 phenotypes—persistent redness of the facial skin or, less commonly, phymatous changes where the facial skin thickens—is considered diagnostic of rosacea. Additional major cutaneous signs, which often appear with the diagnostic features, include papules and pustules, flushing, telangiectasia and certain ocular manifestations. The presence of 2 or more major phenotypes independent of the diagnostic features is also considered diagnostic of rosacea. Secondary phenotypes, which must appear with 1 or more diagnostic or major phenotypes, include burning or stinging, swelling 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, inflammation of oil glands at the rim of the eyelids (blepharitis) and crusty accumulations at the base of the eyelashes, in addition to others.
“Although rosacea’s various phenotypes may appear in different combinations and at different times, research suggests that all are manifestations of the same underlying disease process, and that rosacea may progress not only in severity but to include additional phenotypes,” Dr Gallo said.
The committee also acknowledged the psychosocial effects of rosacea, noting that multiple patient surveys have documented rosacea’s substantial adverse impact on emotional, social and occupational well-being. They stressed that this should also be an important consideration, and suggested the development of appropriate severity scales to measure this dimension, as well as the need for further research to adequately assess rosacea’s negative effects.
The updated classification system was developed to provide standard criteria essential for performing research, analyzing results and comparing data from different sources, as well as to serve as a diagnostic reference in clinical practice. It also serves to provide common terminology for clear communication among a broad range of researchers, clinicians and health officials.