I have been dyeing my hair for the last 20 years, but the last 3 times i started having itching in my hands ,especially the palm of my hands,and it felt better with Benadryl. However the most recent time I developed itches, then my whole body was very hot and i felt pressure in my chest ,i couldn t breathe, i took 2 tabs of benadryl , nausea, i vomited, i felt i could breath again.