"It's damage that's very superficial, usually superficial to the face around the cheeks and around the nose," said Dr. John Swartzberg, who heads the editorial board at the UC Berkeley Wellness Letter.
"It typically begins in the middle years, more common in people who have very fair skin and it's more common in women than men."
There's no cure for Rosacea, but there are treatments. And Dr. Swartzberg says there are some common triggers.
"Hot and cold weather, sun exposure, a lot of emotional stress," he said. "Sometimes spicy foods, even wind blowing hard against your face will do it. Some people find that exercise triggers it or hot baths or hot beverages."
Once you know what they are you can avoid those triggers.
There's a common myth about Rosacea that it's caused by drinking too much.
"It does not cause Rosacea, he said. "But it is true that alcohol is one of the major things that can cause Rosacea to flare."
Fact Sheet on Rosacea