[Epidemiology of rosacea: updated data].

The epidemiological data on rosacea remain fragmentary and the methodological quality debatable. Rosacea affects mainly adults around the age of 30 years and classically predominates in females. Recent Estonian and Irish studies suggest that the female predominance may not be as high as previously believed. However, prevalence does increase with age. The prevalence statistics published in Europe and the United States are highly variable, ranging from less than 1% to more than 20% of the adult population; actually, the methods used and the populations studied vary greatly from one study to another; consequently, they cannot be compared. A family history of the disease is a risk factor, as is the very light skin phototype (Celtic skin type). Alcohol and coffee, classically blamed, are not risk factors; however, tobacco may have a protective effect. New studies are undoubtedly necessary: they should use the diagnostic and severity criteria established in 2002 and 2004. Rosacea has a strong impact on quality of life and can be associated with depressive symptoms. A specific quality-of-life scale, the RosaQol, has been established and validated in the United States, by the same group that elaborated the Skindex scale. Translations of this scale into French, Italian, German, and Spanish have been validated, which may allow future intercultural comparisons.