Does your teen want a tattoo? Here’s another reason to say no.

Whether it’s their favorite sports team, a tribal symbol or pretty little butterfly, teens have varying reasons for wanting tattoos. They crave self-expression, a way to assert independence from their parents, and tangible means to demonstrate their belonging to a group. Tattoos are a very visible way of achieving all of those things.

If you’ve ever tried to talk a teenager out of a tattoo, though, you may have found that your reasoning falls short.

They don’t want to hear that you don’t think it looks good. They think it looks good, and their friends think it looks good and that’s what matters to them. They don’t want to hear that they are going to regret it later (even if you’ve made the same mistake before!). They are absolutely sure that they will want barbed wire around their bicep when they are ninety.

However, there are some important medical concerns that may give them pause.

First there are the well-known risks of infection and transmission of disease. Tattoo equipment that is not properly sterilized can cause bacterial skin infections and transmit blood-borne illnesses such as Hepatitis B and C as well as HIV/AIDS. There are things you can do, though, to minimize this risk. You should be sure that a tattoo parlor:

• Has a clean, well-lit work area
• Sterilizes equipment with a heated machine called an autoclave
• Uses new needles that are sterilized and disposed of after each use (you should be able to watch the tattoo artist open a new package)
• Does not re-use ink

Your teen may say, “Yeah, yeah, yeah, Mom. I know. The place I want to go to is very clean, though.”

But there’s another reason to say no.

The second and less well-known issue that can arise is a severe, ongoing skin reaction. While most people are unaware of this potential complication, new research has shown that 1 out of 10 people with a tattoo will experience a rash, itching or swelling that lasts anywhere from several months to several years.

This often has nothing to do with the practices of the tattoo artist or the cleanliness of the tattoo parlor, but instead has to do with the quality of ink that is used and how the body reacts to it. The ink that is used for tattoos is not regulated by the government (or anyone for that matter), and it’s virtually impossible to know the quality of what’s being injected into your skin. Many patients develop an allergic reaction (known as allergic contact dermatitis) to the ink, and this seems to be more common with red and black inks. These reactions can be treated by a doctor with antihistamines, steroids and wound care, but sometimes the irritation may persist until the tattoo is removed entirely, which is itself a time-consuming and painful process.

There is no way to know whether you’ll be one of the 10 percent who have ongoing problems with their tattoo. There is no way to determine the quality and purity of the ink being injected into your body.

So if your teen has fallen in love with a Chinese symbol that they want to wear on their body for ever and ever and you’ve already tried the, “you’ll regret it later” argument to no avail, try explaining the real medical risk they are taking by getting a tattoo.

They may just decide that it’s not worth all of the problems after all.