Ah, tattoos. To some, they are the pinnacle of artistic expression, to others they are a wearable reminder of past experiences, and to a very unlucky handful, they are the cause of seriously unpleasant medical problems.

After all, though we rarely dwell on the details of the inking process, tattoos are created by repeatedly puncturing the skin with a needle in order to push pigments – whose formulations and production are not regulated by any health and safety oversight agencies – into the tissue layer that contains one’s nerve endings, blood and lymph vessels, sweat and sebaceous glands, and hair follicles.

This dermal trauma and introduction of foreign chemicals can lead to a nasty allergic reaction or bacterial infection that must be treated with anti-inflammatories or antibiotics. And thanks to an unusual case detailed in BMJ Case Reports, there is evidence that the increasingly large subset of people living with weakened immune systems may be at risk of particularly serious forms of these complications.

According to the authors, physicians at a National Health Service (NHS) facility in Glasgow, the 31-year-old woman at the heart of this cautionary tale had been taking immunosuppressants for several years – following a 2009 double lung transplant – when things first went south. Because she had received a tattoo on her right leg that healed uneventfully, she saw no reason not to get one on her left thigh: a lovely tribute to the enduring love of Jack and Sally from The Nightmare Before Christmas. 

Beginning just nine days after the tattoo was completed, she developed pain in her thigh and knee that was so severe she had to request painkillers. Her pain levels lowered somewhat shortly after yet remained bothersome enough over the next 10 months that her primary doctor(s) referred her to a rheumatology department. Wanting to assess the possibility of a joint or muscle disease, the specialists ran a number of tests. They all came back negative.

Finally, a biopsy of her thigh muscle revealed she was suffering from a poorly understood autoimmune condition called inflammatory myopathy. Characterized by persistent pain and muscle weakness, the cause or causes of inflammatory myopathies have been difficult to pinpoint.

“We can’t absolutely prove it was due to the tattoo but because of the timing firstly, with the symptoms coming on one week after she had the tattoo, the location being right underneath where she had the tattoo, it led us to imply there is a link there having exhausted all other lines of inquiry,” co-author William Wilson told The Guardian.

“Nobody knows in most cases what causes inflammation in the muscle, the implication is that it could be something like bacteria that has got in there, or it could be a reaction to a toxin – such as perhaps the ink,” he added.

As there are no proven pharmaceutical treatments for inflammatory myopathy, the physicians recommended physical therapy to prevent muscle atrophy and maintain her range of movement. One year after her symptoms onset, she began to improve; after three years, she was finally pain-free.

“Patients are unlikely to discuss tattoos with medical professionals, even though these might be relevant. Long-term immunosuppressed patients are often young adults who may wish to consider tattooing,” the authors conclude.

“It is well recognised that immunosuppressed patients are at increased risk of infection including cutaneous mycobacterial infections. They therefore represent a group that is at a potentially higher risk of tattoo-related complications and warrant special consideration.”