It wasn't until her tan disappeared that Karin van der Valk noticed the suspicious red patches on her left cheek.

"I thought it was sunburn, but when my tan was all gone in the winter, I realized the red patches were quite prominent," she said.

It took her a while to discover the cause of the redness. "I also have asthma and allergies, and tend to break out in red patches when I'm suffering an attack," she said.

In addition, red facial tones were not uncommon in her family. "My father is from Holland," she said. "He always had redness on his face, but his freckles tended to camouflage it."

About one year after noticing the initial red patches, van der Valk went to see a physician. He thoroughly examined her face under a magnifying glass and told her she had rosacea. He explained the condition's chronic nature of flare-ups and remissions and told her what she could do to help control it. He prescribed a topical cream medication she applies twice a day and suggested she avoid potential irritating factors.

Stress, according to van der Valk, is her greatest rosacea tripwire. "When I am under pressure or nervous, I immediately feel my neck get red, blotchy and hot. Soon after, I see the rosacea."

When her rosacea flares up, van der Valk said she can usually cover it fairly well. "I use a green base stick and foundation."

She also uses a simple skin-care routine. She washes with a mild bar soap and warm water, then applies her medication and a hypoallergenic moisturizer.