Amazing isn't it? Saysuzie is so right, we walk a tightrope.
I find I avoid flares best by staying OUT of the sun. Sunscreen, long sleeves, slacks, and of course my trademark HATS - 4" brim or wider.
Exercise - again a tightrope. But I feel better if I do some every day - walking, biking, eliptical at the gym, light weights.
Eating well - I follow a semi vegitarian diet (I eat fish now and then, expecially wild salmon), high in omega 3 oils (flax, olive) and high in whole foods - whole grains, fresh veggies, beans and lentils. THat has helped me.
I think many of us vary in our specific triggers, but stress, sun and exhaustion are common factors for most of us.
~"I find hope in the darkest of days, and focus in the brightest. I do not judge the universe." (Dalai Lama)