I used the same dye I had used 3 weeks prior .... The 2nd half of the same pack. And then had a reaction. I have tested almost all brands, even those who claim to be ppd free and with one exception I ahve had the same reaction to toluene. The exveltik6 was one particular shade of a brand I allergic to. I found the more expensive lroducts and salon dyes give me the worst reaction. I have medium to darkish brown hair amd K have only found one brand with one colour I like that doesn't have negative results. I don't like natural henna cos it gives me a dull, muddy water colour. And I did cassia and indigo with henna and it didn't work for me. There are some lighter hair colours that might not have the same effect on my scalp but I don't want to go that drastic. I have a warm caramel skin tone (see my profile pics) . I have m6De peace with the fact that I cannot colour my hair. And thats a pity cls my hair looks fuller when warmer coloured.