Why a Little Bit of Ink is a Whole Lot of Infection
In the last few years, hipster subculture has sent today’s youth ringing up secondhand vintage clothing at local thrift shops and vying for the affections of personal baristas at top-choice, around-the-corner coffee shops. But now, it seems like a new trend has them lining up outside parlor doors to engage in a very different sort of patronage: the art of getting inked.
Twenty years ago, tattoos were a simple gesture of rebellion and a form of solidarity, uniting the few who dared to don this bodily artwork. However, with more than 45 million people in the U.S. today with tattoos of some sort, it has become less of a symbol characterized by stigma and non-conformity, and more of a convenient outlet for self-expression. With no signs of slowing down, the art of tattoos has expanded into its own trade, even inspiring Pinterest pages and infiltrating competitive reality television. In fact, the U.S. alone has more than 21,000 parlors across the country and spends about 1.65 billion dollars a year on tattoos. Despite the obsession that today’s young generations have with tattoos, rarely does anyone ever stop to think about how tattoos actually work — even when they’re about to go under the needle!
Usually, most people only worry about the sting of the pulsating needle or the potential criticisms by parents and employers when deciding whether to get a tattoo. However, the mechanism of how a tattoo is applied and manages to stay permanently within the body should be of much more concern than whether or not mom will approve of the Popeye stamp on your left deltoid.
Now, how exactly does a tattoo work? People often assume that the tattoo artist just applies the pigment really deep in the skin so that it endures regardless of the number of showers you take or the layers of surface skin that are replenished over time. However, considering that we lose more than a million skin cells a day, it wouldn’t take so long before our tattoos went along with the dead skin.
Rather, the skin is made up of two major layers; the external layer that gets shed over time is the epidermis and the dense inner layer of skin beneath the epidermis is the dermis, which protects the tissues underneath. Instead of merely penetrating the outer epidermal layer, the tattooist’s pulsating needles make it all the way into the dermal layer, at which point the pigment is actually released.
Now, think about when you get a shot at the doctor’s or when you scrape your knee — your skin flares up, which is part of your immune system’s inflammatory response. The inflammatory response is your body’s attempt to figure out what is happening at the point of injury and to assess what needs to be repaired. In the case of getting a tattoo, the body starts an inflammatory response in the body to investigate what’s happening at the puncture wound where the needle entered and to repair the skin.
Once the body has been alerted that suspicious activity is going on, it signals for a horde of special white blood cells, called macrophages, to come to the rescue. Macrophages are the same cells that mobilize when you’re sick from a cold to gobble up any pathogens in your body like an immunological Pac-Man. Since the pigment is in the dermis — a deep layer infused with a network of blood vessels and nerves — the macrophages rush through this system of vessels and try to eat up some of the dye once they reach the dermis. Some but not all of these macrophages will act as the body’s police officers, shuttling the perpetrators — the dye particles — downtown to the police station of the body, the lymph nodes, the same place where other foreign particles such as cancer cells are dealt with and filtered out. Unfortunately, some of these macrophages that have successfully captured their culprits won’t make it out of the dermal layer to get to a lymph node. The dye that hasn’t been engulfed by macrophages will be absorbed by specialized dermal cells called fibroblasts. Even when these dye-filled fibroblasts die, they’ll be engulfed by other dermal cells and will continue to stay in limbo in the dermis.
The combination of dye in both macrophages and fibroblasts that are forever suspended in the dermal layer is what makes tattoos permanent and visible through the skin.
But if these cells carrying the dye never leave the dermal layer and won’t get shed by the body along with other dead skin cells from the epidermis, then why do tattoos fade over time? Part of the reason is that the body’s macrophages eventually manage to slowly break down some of the dye particles to export them out to the lymph nodes, but this only applies to a few of the particles. In this case, the sun is the culprit for the overall fading of tattoos. Just as sunburns can hurt the skin by causing dramatic peeling of the epidermis and long-term damage to the dermis, which can result in skin cancer, UV rays from the sun can also penetrate the skin and break apart the dye particles in the dermis layer. As bulky dye particles are degraded into smaller chunks, the body’s repair system can more easily filter them out, resulting in the gradual faintness of the tattoo over time.
So if a tattoo only lasts because your body identifies it as a perpetual infection and constantly attacks the dye, then what should you do if you want it removed? If your graceful, white-tailed sparrow has lost its charm since you were a teenager or you no longer want your ex’s name imprinted across your collarbone, laser tattoo removal is definitely the safest way to go. It sort of works in the same way that the UV rays of the sun do when causing gradual fading of the tattoo, but in a more directed, concentrated manner. In a process that requires multiple sessions, lasers blast through the epidermis, breaking apart dye particles so that macrophages can once again return and export the smaller fragments. Unfortunately, depending on the quality of the tattoo application (professional or amateur) and the specific colors of the dye, certain tattoos can be harder to remove than others, and the treatment may even result in permanent scarring. For example, black is the easiest pigment to break down with a laser, while lighter and brighter colors are much more difficult, requiring higher-powered lasers with shorter wavelengths. This is why fluorescent or light pigments result in more painful procedures that can result in discoloration of the skin and inflammation at the site of treatment.
So before your love of Nietzsche has you scurrying over to the closest tattoo parlor to have “God is dead” imprinted across your chest, think about what a tattoo could mean for your body beyond a fashion statement. Your macrophages might appreciate it.