Fig. 4.

Tattoo needle wear biodistribution and supposed contribution to allergy formation. Nickel and chromium containing wear particles are abraded by titanium dioxide containing inks. The steel used to manufacture tattoo needles contains 6-8% nickel and 15-20% chromium. Pigments and wear particles are inserted into the dermal part of the skin. Both are passively and actively transported to the draining lymph nodes where Ni²⁺ ions as sensitizing species of nickel can be released. Antigen presentation to T-cells takes place in the lymph nodes as part of the adaptive immune response which is an obligatory process for sensitization and thus type IV allergy formation in the skin