Allergic contact dermatitis to 1,4-bis(isopropylamino)anthraquinone. Caused by a felt-tip marker pen.

Adult allergic contact dermatitis to the black ink of a felt-tip marker pen occurred in two adult subjects. In both subjects the cutaneous reaction did not require photoactivation. Patch testing with the ingredients in the black ink demonstrated cutaneous sensitivity to the black dye. Further patch testing with the components of the black dye revealed cutaneous sensitivity in both subjects to the blue component, 1,4-bis(isopropylamino)anthraquinone, commonly known as Colour Index Solvent Blue 36.