The following are the primary complications that can result from tattooing:

o Infection. Unsterile tattooing equipment and needles can transmit infectious diseases,such as hepatitis. The risk of infection is the reason the American Association of Blood Banks requires a one-year wait between getting a tattoo and donating blood.

It is extremely important to make sure that all tattooing equipment is clean and sterilized before use. Even if the needles are sterilized or never have been used, it is important to understand that in some cases the equipment that holds the needles cannot be sterilized reliably due to its design. In addition, the person who receives a tattoo must be sure to care for the tattooed area properly during the first week or so after the pigments are injected.

o Removal problems. Despite advances in laser technology, removing a tattoo is a painstaking process, usually involving several treatments and considerable expense. Complete removal without scarring may be impossible. See "The Most Common Problem: Dissatisfaction" and "Removal Techniques," below.

o Allergic reactions.Although allergic reactions to tattoo pigments are rare, when they happen they may be particularly troublesome because the pigments can be hard to remove. Occasionally, people may develop an allergic reaction to tattoos they have had for years.

o Granulomas.These are nodules that may form around material that the body perceives as foreign, such as particles of tattoo pigment.

o Keloid formation. If you are prone to developing keloids -- scars that grow beyond normal boundaries -- you are at risk of keloid formation from a tattoo. Keloids may form any time you injure or traumatize your skin.Tattooing or micropigmentation is a form of trauma.

o MRI complications. There have been reports of people with tattoos or permanent makeup who experienced swelling or burning in the affected areas when they underwent magnetic resonance imaging (MRI). This seems to occur only rarely and apparently without lasting effects.

There also have been reports of tattoo pigments interfering with the quality of the image. This seems to occur mainly when a person with permanent eyeliner undergoes MRI of the eyes. Mascara may produce a similar effect. The difference is that mascara is easily removable.

The cause of these complications is uncertain. Some have theorized that they result from an interaction with the metallic components of some pigments.

However, the risks of avoiding an MRI when your doctor has recommended one are likely to be much greater than the risks of complications from an interaction between the MRI and tattoo or permanent makeup. Instead of avoiding an MRI, individuals who have tattoos or permanent makeup should inform the radiologist or technician of this fact in order to take appropriate precautions, avoid complications, and assure the best results.