Cause Unknown
Although scientists have yet to determine the exact cause of rosacea, they believe it’s probably some kind of combination of genetic susceptibility to develop rosacea, and environmental factors, with the sun playing the biggest role.
Environmental Factors
Environmental factors are being investigated as possible causes of rosacea flares and acne-like pimples in patients with rosacea. Mites that live in our skin, particularly in hair follicles, (Demodex folliculorum), have been found in increased numbers in people with rosacea pimples. The role of these mites in actually causing the acne-like reaction in rosacea patients remains to be proven, although treatments aimed at eliminating these mites have been effective at controlling pimples in rosacea patients.
Alcohol Not a Cause
One common misperception about rosacea is that it’s caused by alcohol. Although drinking alcohol can trigger the flushing associated with rosacea, many people who develop the condition are non-drinkers. W.C. Fields is a frequently-cited example of a rosacea sufferer where his symptoms were attributed to drinking alcohol.
Common Triggers
While the cause of rosacea appears to be a genetic predisposition to create veins from long-term sun-exposure, many stimuli can lead to rosacea flare-ups by causing the small blood vessels in the skin to dilate. These triggers include consuming alcohol (especially red wine), drinking coffee or tea, soup, and other hot beverages, eating spicy foods, exercising; going out in cold or hot/humid weather, and even experiencing stress (who doesn’t have this?).
Biggest Trigger: the Sun
The most common trigger of rosacea symptoms, as well as the main cause of the broken (extra) blood vessels on the faces of rosacea sufferers, is sun exposure. In one survey, 81 percent of people with rosacea cited sunlight as a major factor leading to flare-ups.
In fact, people with rosacea who drive a lot tend to have more symptoms on the left side of their face, which faces the drivers’ side window, or on the right side if in England or Australia where they drive on the opposite side of the car.. Since modern car windows block the burning UVB rays, but only about 30% of UVA rays. This tells us that the non-burning (but still skin-damaging) UVA rays are probably a big contributor to not only rosacea, but also to skin cancer and other UV-induced skin changes. So the most important preventive measures for slowing the development of rosacea is to wear sunscreen every day to sun-exposed skin, get UV-blocking window film on your car, and wear brown sunglass lenses (blocks more of the energetic blue/green rays) with a hat.