Health risks

Modern tattoo artist's nitrile gloves and sterilized equipment

Because it requires breaking the skin barrier, tattooing may carry health risks, including infection and allergic reactions. In the United States, for example, the Red Cross prohibits a person who has received a tattoo from donating blood for 12 months (FDA 2000), unless the procedure was done in a state-regulated and licensed studio, using sterile technique.. Not all states have a licensing program, meaning that people who receive tattoos in those states are subject to the 12-month deferral regardless of the hygienic standards of the studio. Similarly, the UK does not provide certification for tattooists, and so there is a six month waiting period without exception.

Modern western tattooers reduce such risks by following universal precautions, working with single-use items, and sterilizing their equipment after each use. Many jurisdictions require that tattooists have bloodborne pathogen training, such as is provided through the Red Cross and OSHA.

Infection

Since tattoo instruments come in contact with blood and bodily fluids, diseases may be transmitted if the instruments are used on more than one person without being sterilized. However, infection from tattooing in clean and modern tattoo studios employing single-use needles is rare. In amateur tattoos, such as those applied in prisons, however, there is an elevated risk of infection. To address this problem, a program was introduced in Canada as of the summer of 2005 that provides legal tattooing in prisons, both to reduce health risks and to provide inmates with a marketable skill. Inmates were to be trained to staff and operate the tattoo parlors once six of them opened successfully.

Infections that can theoretically be transmitted by the use of unsterilized tattoo equipment or contaminated ink include surface infections of the skin, herpes simplex virus, tetanus, staph, fungal infections, some forms of hepatitis, tuberculosis, and HIV. People with tattoos are nine times more likely to be infected with hepatitis C, according to a study by Robert Haley, MD, chief of epidemiology at the University of Texas Southwestern Medical Center in Dallas.

No person in the United States is reported to have contracted HIV via a commercially-applied tattooing process. Washington state's OSHA studies have suggested that since the needles used in tattooing are not hollow, in the case of a needle stick injury the amount of fluids transmitted may be small enough that HIV would be difficult to transmit. Tetanus risk is reduced by having an up-to-date tetanus booster prior to being tattooed. According to the Centers for Disease Control and Prevention no data indicates an association between tattooing in the United States and increased risk for HCV infection. In 2006, the CDC reported 3 clusters with 44 cases of methicillin-resistant staph infection traced to unlicensed tattooists

Allergic reactions

Perhaps due to the mechanism whereby the skin's immune system encapsulates pigment particles in fibrous tissue, tattoo inks have been described as "remarkably nonreactive histologically". Allergies to latex are more common; many artists will use non-latex gloves when required.

Allergic reactions to tattoo pigments are uncommon except for certain brands of red and green. People who are sensitive or allergic to certain metals may react to pigments in the skin with swelling and/or itching, and/or oozing of clear fluid called serum. Such reactions are quite rare, however, and some artists will recommend performing a test patch. Due to the fact that laser removal of tattoo ink causes a release of ink into the bloodstream the risk of anaphylactic shock is also present during removal.