Decorative tattoos are achieved by the introduction of particles of pigment into the dermis with an electric needle. Amateurs prick particles of soot or Indian ink into the skin with a pointed object. Carbon, iron oxides, cobaltous aluminate, cadmium sulphide, cinnabar and vegetable dyes are commonly employed pigments. Complications may arise when infection is introduced (erysipelas, syphilis, tuberculosis, hepatitis, warts and HIV) or when allergic reactions to pigment occur. Some skin disorders show a predilection for tattooed skin, in which they may appear first or be accentuated, e.g. syphilis in the secondary or tertiary stage, lichen planus, psoriasis and sarcoidosis.