Karolina Jasko’s nails were usually painted during her senior year of high school, so she didn’t notice the black vertical line on her right thumbnail until a nail technician pointed it out—and at the time, she didn’t think much of it.

When that same nail started to show signs of infection, however, she decided to seek medical attention, and she was shocked to be diagnosed with nail melanoma.

“My mom was freaking out even more than I was, I think, because she had melanoma before, so she knew what it was like,” says Jasko, now a University of Illinois at Chicago student who is currently reigning as Miss Illinois USA 2018.

Three surgeries later, Jasko’s thumbnail is gone, but so is her melanoma.

“I’m a little self-conscious about it, but I was lucky,” she says. “The doctors originally thought they would have to remove my whole thumb, and you never realize how much you use your right thumb until you think about losing it. And if I had waited any longer to see a doctor and have my first surgery, the melanoma could have spread through my whole body, and it would have been a lot worse."

As Jasko’s story shows, early detection of nail melanoma is important, says board-certified dermatologist and nail specialist Shari Lipner, MD, PhD, FAAD. Because the disease is commonly overlooked and diagnosed late, she says, it often has a poor prognosis, which could result in the amputation of the affected finger or even death.

“It’s important to regularly examine your whole body for signs of melanoma and other skin cancers, and that includes your nails,” she says.

According to Dr. Lipner, ultraviolet radiation exposure is likely not an important risk factor for nail melanoma, as it is for melanoma of the skin. Instead, she says, the two main risk factors for nail melanoma are previous nail trauma and a personal or family history of melanoma. Although anyone can develop nail melanoma, she says, the incidence is higher in older individuals and people with skin of color.

The main sign of nail melanoma is a brown or black band in the nail, often on the thumb or big toe of one’s dominant hand, Dr. Lipner says. However, there are many other potential causes of such dark bands, most of which are benign, she says, including blood under the nail as the result of injury or overly tight shoes, a bacterial or fungal infection, or residual pigment from substances like silver nitrate or newspaper print.

Additional warning signs that distinguish nail melanoma from other causes of dark nail bands include the presence of pigment on the adjacent skin, splitting or bleeding of the nail, or infection-like symptoms such as drainage, pus and pain, Dr. Lipner says. As with other types of melanoma, she says, any change to the nail is also an important warning sign.

“Because early detection plays such a big role in nail melanoma prognosis, it’s important to keep an eye on your nails and be aware of any changes to them,” Dr. Lipner says. “If you notice a new dark band on your nail, or any band that is getting wider or darker, you should see a board-certified dermatologist as soon as possible.”

Jasko agrees. “People may not realize that you can get melanoma in your nails, but it’s important to be aware of that risk,” she says. “If you have the slightest concern about something on your nail, go and get it checked out by a dermatologist; it could end up saving your finger—or your life.”