It started as a tiny rash on Nicole Burwell's calf, appearing at the end of a trip to Las Vegas with her fiancé late in the summer of 2010. “I had this super, super itchy spot on my leg, but not like a mosquito bite. Not raised, not a bump. I couldn't get it to stop itching,” she says. So Burwell, then 40, took the over-the-counter antihistamine Benadryl and slept the entire four-hour car ride home to Claremont, Calif. “It knocked me out,” she says, but when she woke, the itch was still there. Over the next week the rash grew and with it the itch, so Burwell saw her doctor. “By then it had spread to both legs.” For the next three years Burwell would battle an angry, weeping red rash that moved around her body, covering her arms and legs, hands, torso and back. But as ugly as the rash was, it did not bother Burwell nearly as much as the itch.