Why Is Rosacea Considered to Be an Inflammatory Disorder?
The Primary Role, Clinical Relevance, and Therapeutic Correlations of Abnormal Innate Immune Response in Rosacea-Prone Skin

June 2012 | Volume 11 | Issue 6 | Original Article | 694 | Copyright © June 2012


The pathophysiology of rosacea has undergone renewed interest over the past decade, with a large body of evidence supporting the role of an abnormal innate immune response in rosacea. Many mechanisms interact with the cutaneous innate immune system that may be operative. A variety of potential triggers stimulate this immune detection system which is upregulated and hyper-responsive in facial skin of patients with rosacea as compared to normal skin. Based on the most current data, two conclusions have been reached. First, the major presentations of rosacea appear to be inflammatory dermatoses. Second, the presence of a microbial organism is not a primary or mandatory component of the pathogenesis of rosacea. Available therapies for rosacea exhibit reported modes of action that appear to correlate with the inhibition of inflammatory processes involved in the pathophysiology of at least some presentations of rosacea.

J Drugs Dermatol.2012;11(6):694-700.


Rosacea is well recognized globally as a common dermatologic disorder encountered in clinical practice. Although prevalence estimates vary depending on the population evaluated and the methodology used to capture the diagnosis for demographic or epidemiologic purposes, there is little disagreement that at least the major presentations that have been classified as rosacea are commonly encountered in clinical practice.1-4 For the purposes of having a reasonably accepted "diagnostic language" for discussion, the common presentations of rosacea were first designated as subtypes in 2002, and subsequently in other references. 2 Among the four major subtypes, the two most common are erythematotelangiectatic rosacea (ETR) and papulopustular rosacea (PPR). Although rosacea has long been recognized as being most common in patients with very fair skin with a reported prevalence of up to 10% in individuals of Northern European or Celtic heritage (Fitzpatrick Skin Type I-II), it has also been reported to affect approximately 4% of individuals with darker skin types.5-7 To add, there is some evidence that African Americans are more likely to be affected by rosacea if one of the parents is of Northern European ancestry.8 Nevertheless, a thorough evaluation of the prevalence of rosacea, including a breakdown of individual subtypes or specific presentations, has not been completed in patients with skin of color (Fitzpatrick Skin Types IV-VI) or among different ethnicities where darker skin types than Fitzpatrick I-II are predominant.

Clinical Differentiation of Common Presentations of Rosacea

Clinical features that characteristically manifest in ETR that are also observed in many patients with PPR include diffuse central facial erythema, telangiectasias, and associated symptoms (ie, stinging, burning) and signs (ie, scaling, flaking, redness) of "skin sensitivity" and stratum corneum (SC) permeability barrier impairment.1-5,8 PPR differs clinically from ETR by the presence of inflammatory lesions in PPR. The inflammatory lesions of PPR are commonly papules and pustules that are most pronounced on the central face with associated perilesional erythema, although some patients with PPR may have few or many inflammatory lesions with little to no diffuse central facial erythema that is not perilesional in nature.1-3,8-11