[Tattoo and sarcoidosis reaction].

The practice of tattoo is developing more and more all over the world. Infections are known. but chronic inflammatory reactions have often resulted in a variety of clinical manifestations. In addition to allergic reactions, non-allergic reactions prevail in black tattoos and manifest themselves as "papulonodular" lesions. The importance of biopsy of papulonodular lesions to confirm the diagnosis should be emphasized. Carbon black nanoparticles agglomerate in the dermis over time to form sarcoid granulomas. Pigment-bound foreign-body granuloma and sarcoidosis are often difficult to distinguish. The black color seems to be the most common. Other aetiologias than pigment are evoked, such as the role of an infectious agent, but to date none has been identified, a particular genetic terrain remains to be defined. Systemic localizations being possible, the extension assessment is important to carry out. It is also important, as a preventive measure, that subjects and their treating physician be informed of the potential risk associated with these drugs indicated for specific serious pathologies.