Research indicates that 10% of people with tattoos experience some sort of complication, such as pain or infection. While their first inclination may be to seek help from the artist who gave them their tattoo, it may be necessary to see a board-certified dermatologist for the proper diagnosis and treatment of skin problems.

Some common tattoo complications include infections, allergic reactions, and worsening of an existing skin condition such as psoriasis or eczema, says Marie Leger, MD, PhD, FAAD, a board-certified dermatologist in New York. Sarcoidosis, an autoimmune disease that can affect the skin and other organs, sometimes first appears with bumps at the site of a tattoo, she says.

Infections are more common within the first couple of days or weeks of getting a tattoo, Dr. Leger says, and they can cause redness and pain around the site of the tattoo (not just on the actual ink), drainage, crusting, and pus. “If you experience these symptoms after getting a tattoo, see a doctor right away, because infections can be quite serious,” Dr. Leger says.

Allergies and sarcoidosis may pop up later—months to years after getting a tattoo, Dr. Leger says. Signs of these conditions may include itching, bumps, scaling, periodic swelling, or the tattoo becoming raised, she says, adding that anyone experiencing these symptoms should visit a board-certified dermatologist, rather than a tattoo artist.

“Dermatologists and tattoo artists have different categories of things that they’re good with,” Dr. Leger says. “Artists can assess cosmetic issues like ink migrating from the tattooed area to the surrounding area, and they’re used to seeing normal tattoo healing, so they can be a useful source of information about that. Dermatologists can really help manage things like infections or chronic reactions that pop up a little later.”

Dr. Leger recommends that those experiencing complications notify their tattoo artist in addition to visiting a dermatologist. “It is important for artists to know if particular patients are having complications so they can be a part of assessing what’s going on,” she says.

According to Dr. Leger, tattoo infections can come from contaminated ink, unsterile application, or improper care after the tattoo is applied. In 2012, for example, an outbreak of tattoo infections in New York was traced back to a rare bacteria found in certain gray ink, which was then recalled. “It can be tough, because some of these things that can go wrong are in the control of artists and clients, and some aren’t,” Dr. Leger says.

Opened ink bottles can have more infection-causing bacteria than new bottles, she says, and it’s possible for ink to become contaminated when artists mix colors or dilute with non-sterile water, which includes distilled water. She says it’s important choose a reputable tattoo artist and diligently follow his or her care instructions.

Dr. Leger recommends that those with chronic skin conditions or a history of skin cancer talk to a board-certified dermatologist before getting a tattoo. People with psoriasis should be aware that they may develop a patch of the condition on their tattoo, she says, and those with moles should avoid tattooing over them. “There’s no strong data that shows tattoos increase your risk of skin cancer,” she says, “but they can make detection harder.”

Nearly 40% of people born after 1980 have tattoos, Dr. Leger says, so it’s important for dermatologists to be aware of potential tattoo issues and for tattoo artists to be aware of potential skin issues. To that end, she gives lectures and teaches classes for tattoo artists about skin cancer detection and preexisting skin conditions, and she also encourages her fellow dermatologists to make sure they examine patients’ tattoos and look for any medical problems that may appear there.

Dr. Leger also wants the tattooed population to know that a dermatologist can help if they experience complications. “Dermatologists are the experts on skin,” she says, “so if your tattoo results in a skin problem, see a board-certified dermatologist for diagnosis and treatment.”