Rosacea is a common but under-diagnosed condition of the facial skin that affects around 10% of all individuals. Rosacea is most likely to affect fair skinned, Caucasian people but is also seen in people of Asian and African origin.
The exact cause of rosacea is not yet clear but hypotheses include Helicobacter pylori infection, Demodex folliculorum (a tiny insect) infestation, abnormal skin vasculature, high blood pressure, the menopause and environmental triggers such as exposure to wind, extreme heat or the sun.
In the United States, the prevalence of rosacea seems to be on the rise and in the United Kingdom, the prevalence is 1.65 per 1000 person-years.
There is a paucity of epidemiological data on rosacea, with reported prevalence rates ranging from as little as 0.09% to as much as 22.00%.
The condition is most common among individuals aged 30 to 50 years and women are two to three times more likely to be affected than men, with women of menopausal age at a greater risk still.
The condition often goes undiagnosed among dark-skinned individuals who may have a different clinical presentation to fair-skinned people and suffer more from complications such as conjunctivitis and blepharitis (eyelid swelling).
One of the more severe complications of rosacea is rhinophyma or disfiguration of the nose, a manifestation that occurs most commonly among men.
In one study7 examining the prevalence of rosacea subtypes, 14.8 % of women had type 1 or erythematotelangiectatic rosacea while only 1.5% had the second type, papulopustular rosacea. For this study the researchers looked at mainly Caucasian women from the cities Rome, London, Los Angeles and Akita (from Japan). Type 2 rosacea was the most prevalent in American women compared with those of other ethnicities.