Rosacea is an inflammatory and chronic dermatosis that predominantly affects the face, rosacea is characterized by a widespread and diffuse redness, sometimes accompanied by the dilation of small blood vessels, making them visible. Other symptoms often accompany this disease, such as hot flashes, skin hypersensitivity, or burning sensations. In some cases, rosacea can progress and lead to the appearance of pimples, significant skin thickening, or even affect the eyes.
While the causes of rosacea are still poorly understood and seem to be multifactorial, one hypothesis stands out in the scientific community: that of a genetic predisposition to develop this skin condition. This suspicion comes notably from the frequency of rosacea occurrence in individuals with very fair skin and eyes. It has indeed been observed that people from Northern Europe, who predominantly have phototypes I to III, are more affected by the disease than those with darker skin.
According to some epidemiological data, up to 30% of individuals with rosacea have a family history of this condition.
A study conducted by POPKIN in 2015 aimed to highlight the link between genetics and the development of rosacea. For this purpose, 233 pairs of monozygotic twins and 42 pairs of dizygotic twins, totaling 550 individuals, were surveyed to determine if they exhibited symptoms of rosacea. As a reminder, monozygotic twins share almost 100% of their genetic material, while dizygotic twins share about 50% of their genes. By observing the incidence of rosacea among the different twins, as well as their lifestyle habits, the researchers were able to establish a genetic correlation percentage, evaluated here at 46%. According to this study, rosacea appears to be attributable in equal parts to genetic factors and environmental factors, such as exposure to UV rays, alcohol consumption, or smoking.