One in four people in the USA have at least one tattoo and in Europe there are about 100 million tattooed bodies. Permanent skin adornment is growing in popularity especially amongst the younger generations.

Tattoos like laser treatments are on the cusp between medicine and beauty. Medically tattoos have a variety of uses: to imitate hair, mark radiotherapy coordinates and even record immunizations.

But most tattoos are the result of a cosmetic not medicinal activity. Fortunately, due to improved practices in tattoo parlors the health risks are small. Less than 5% of people get infections after getting a professional tattoo and the worries about getting hepatitis C and HIV are unfounded.

There should be breathalysers at tattooing sites to prevent drink dyeing.

However, there are new reports of a delayed problems from infections. Mycobacterial infections surface a month or so after tattooing. One of the major sources of this infection is the distilled or tap water, which is used to dilute the ink for shading. So beware grey shading in your basic black tattoo.

Itching, not infections, still remains the most common side effect and the main reason why people seek care. For some patients it is as bad as having a skin condition like psoriasis. Black and red dyes most commonly cause allergic reactions, probably due to residual metals in the largely natural dyes that are now used. Henna used in temporary tattoos contains known allergens such as paraphenylenediamine. Fortunately, less than 5% of people get allergic reactions from the dyes – irrespective of color.

However, the consequences of tattoos are more than skin deep. Regret is a more common side effect. One in 5 people who get tattoos say they had them done when they were drunk and had diminished capacity for informed consent. Over 20% of people who get tattoos want them removed and this process is as painful and more expensive than the original tattoo.

Although there is no association of cancer with tattooing, melanoma, the most deadly skin cancer, can be obscured even if the tattooist is zealous in avoiding tattooing over moles.

Most of this information comes from small studies which have not been reproduced. As the number of people getting tattoos increases there is a need for well-designed studies to help establish a scientific basis for understanding the impact of tattoos and ensure safety, in addition to health education about the risks of adverse reactions.

In the meantime, tattoo inks should be classified as medicinal products so they can be regulated. There should also be breathalysers at tattooing sites so that people who do not have the capacity to fully consent are prevented from drink dyeing.