Hmmm...that's a good question!
I know from my experience I cannot tolerate sitting in those salon chairs and ESPECIALLY with my head back getting washed and rinsed in the sinks! It will definately send me into a nasty flare for quite awhile. I'm also sensitive to the dyes and chemicals they use, as well, which will trigger migraines in me, so needless to say, I don't dye my hair! If I do get brave and dye my hair, (Lol!) which I have a few times, I usually pick up one of the kinds at the stores and do it at home myself since that way I have more control over making sure there's plenty of ventilation and air in the room while I'm doing it. I think some of the store-bought ones are possibly less harsher than getting it done at a salon and they seem to be getting better as far as "smell" goes. I also find that hairstylists can be pretty rough sometimes, so I always make sure to tell them I have chronic pain and to "go easy" on me! If they don't then I find myself a new hairdresser!
Dini