Itchy Skin for over a year, allergic to the black dye in ...

Hi,
I have always had minor reactions to coloring my hair black, but about a year and a half ago I dyed my hair and the reaction was severe. Usually the itchiness and redness was limited to my scalp and around the hairline, but this time it was all over my body. Ever since then, I have had chronic itchy skin on my face, back, legs and arms (not on my scalp). I was prescribed Valisone scalp lotion, which eases the itchiness, but it has never completely gone away. I have not dyed my hair since this incident. I discussed this with my doctor and we came to the conclusion at the time that I may have become allergic to the black dye in my clothes, since that was the primary color in my wardrobe. I tested the theory and the symptoms were reduced, and worsened greatly if i wore black clothing for too long. I have since bought non black clothing, but the itchiness has not permanently gone away. I have tried scent free detergents and tried stopping any harsh soaps, but neither had any effect. Any idea what could be causing this? Is it possible that I've become allergic to any form of dye in clothing?