Granuloma is a chronic proliferative inflammatory reaction surrounded and delimited by healthy tissue (Rabinowitz 1996). The penetration into the skin of a number of insoluble, non-degradable and slowly released substances may give rise to a foreign-body granulomatous reaction. These substances include wood, silk, nylon, paraffin, silicon, talcum powder, starch, oils, animal and vegetable spines or bristles, vaccine (Jones 1996) and human hair. Histology distinguishes two types of granuloma: the more frequent foreign-body granuloma and a second so- called allergic granuloma. This type of reaction, i.e., contact allergic granulomatous reaction, has been described in subjects sensitized to zirconium, beryllium and some tattoo colorants. A foreign-body granuloma may “transform itself” into an allergic skin granuloma when the etiologic agent remains in the lesion for some time and, in the final analysis, behaves as an allergen.
