I discussed hair dyes with my hairdresser once, who said it was possible to dye the hair but not let it go onto the scalp. I can't believe this would work as you would have a gap, like a 4 week growing out mark.

Are there any non permanent dyes that don't contain these chemicals, that your hairdresser could use?

I probably depends how they affect you as to continuing their use.

Good luck

Loo