What does Black henna mean?

Black henna meaning in Medical Dictionary

A tattoo ink and paste comprising henna along with other components included, often including para-phenylenediamine (PPD). Allergic reactions to PPD feature a contact dermatitis, itching, blisters, open sores, scarring of your skin . Allergies to PPD could also cause sensitiveness to many other items like hair dye, sunlight block plus some kinds of black colored clothes. Also known as blue henna.