Although the most common problem with tattoos is that people later want them removed, tattooing can also be a health hazard. Unsterilized equipment can transmit diseases such as AIDS and hepatitis. Many pigments used in tattoo inks are not approved for skin contact, much less injection. (Some are industrial-grade colours that are suitable for printers ink or automobile paint.) The pigment can migrate into unwanted areas. Some people also develop allergic reactions to the inks and some experience swelling or burning in the tattooed areas if they undergo magnetic resonance imaging (MRI).
Tattooing is a traditional form of body decoration in many cultures and is probably as old as humanity. It is done by jabbing bits of ash, charcoal or ink under the skin to create permanent designs. One 6,000-year-old mummy has several tattoos.
Dermatologists remove tattoos with improved lasers. Because the pulse is so short, the heat generated does not have time to damage the skin. The ink is dispersed into tiny pieces to the lymph nodes where it stays forever. Laser specialists precisely match the type of laser with the colour of the ink in the tattoo, choosing a laser that is a complementary colour to the ink in a tattoo, eg. green lasers are used to remove red ink. But matching the laser to the colour of the ink is tricky because of the variety of inks used. This means clinics need many different, expensive lasers - one reason that tattoo removal can cost US$1,000 or more, far more than the original tattoo. Whilst some pigments are easily removed, for green and purple ink the chances of removal are worse than 50-50. Some tattoos used as a kind of permanent makeup (eg. lip and eyeliners) can be particularly difficult to remove, especially if the ink contains oxides of iron or titanium.
Over the last 20 years, the number of tattoo studios in the USA has risen from 300 to more than 4,000. About half of the states now have regulations governing the practice.
In 2000, about 18 percent of US college students now have tattoos. Women now account for half of all tattoo recipients. Many people now get tattoos not as a fashion statement but to simulate natural pigmentation after breast or facial surgery, to create artificial eyebrows in certain hair loss conditions or to make discoloured skin look more normal despite a skin disease called vitiligo.
A study was made in the USA of 626 men and women who did not know their hepatitis status and came into an orthopaedic clinic for reasons unrelated to hepatitis. Nearly a fifth of participants had a tattoo. Of those who had a tattoo, 22% were infected with hepatitis C, and of those who had it done at commercial parlours (as opposed to in their own homes), 33% had the disease. Only 3% of people without a tattoo had hepatitis C.