I have flare ups all the time and I'm not that good pin pointing the cause. I'm working on this area. I do know that my flare ups can last just a few hours to weeks. I don't know if food at this point contributes, I do know heat, stress, weather, overall well being (sickly), types of fabrics, all shoes, sitting to long, standing to long and not moving around. But the big ones for me would be heat, and overall well being and over doing it.