This may scare you straight out of that nail-biting habit.

By Susan Brickell
September 07, 2018

You've heard the stories: A nail salon technician identifies a strange black line under a client's nail as a sign of melanoma. Skin cancer does not discriminate, and there are body parts like your hands that can become an unsuspected place for the deadly disease, as a 20-year-old college student from Australia recently found out. Courtney Whithorn had her thumb amputated after doctors detected a rare form of melanoma there.

Whithorn began biting her nails as a coping mechanism after being bullied at school. "During my last year of school in 2014, I was bullied to the point where even the thought of going to school gave me anxiety, so much so that biting my nails became a coping mechanism," she wrote in a recent Facebook post. "Due to the stress and anxiety, I didn’t even realize that I had totally bitten my entire thumbnail off until I saw blood on my hand."

The nail never grew back properly, and the skin underneath the nail darkened, the Daily Mail reported. Embarrassed, Whithorn kept her thumb concealed for four years, hiding it and covering it with fake nails. She finally showed her parents this year when the black color began to worry her.

Whithorn saw a doctor who then referred her to a plastic surgeon, but before surgery to remove the blackened part of the nail bed, surgeons realized something was seriously wrong, the Sun UK reported. They took a biopsy of the area, and, after additional tests, she was diagnosed with acral lentiginuous melanoma or ALM, a form of cancer that affects nail beds, the palms of hands, and the soles of feet. After several surgeries attempting to remove the malignant cells, doctors were forced to remove her thumb completely to keep the cancer from spreading further.

RELATED: 10 Things Your Hands Can Reveal About Your Health

In her Facebook post, Whithorn shared a photo of herself in the hospital after her thumb had been amputated above the knuckle. She thanked her friends, family, and the medical team for seeing her through the challenging experience and used her situation to shed some light on bullying and its effects.

"Please make sure you think about what you say to and about people, because you truly have no idea the psychological, emotional, and physical impact it can have on someone," she wrote.

She's since placed her studies on pause while she recovers and waits to find out if the cancer has, in fact, traveled to any other part of her body. According to her Facebook post, Whithorn believes that biting her thumbnail off was what caused the melanoma in the first place. Which made us wonder: While nail-biting can have some alarming health consequences, is cancer really one of them? We had experts weigh in.

"Many people think that it’s a coincidence that people develop a melanoma under the nail after trauma," says dermatologist Debra Jaliman, MD. "Yet some believe that the trauma may induce a melanocytic proliferation and thereby the melanoma."

Not enough studies have been conducted to find a direct connection between trauma and the formation of these types of melanomas, adds dermatologist Rachel Nazarian, MD. Although this type of melanoma is very, very rare, she says she has seen it several times before in young women who also had to have their fingers amputated. "It’s more likely that areas like the fingernails are manipulated through fingernail-biting, picking, and camouflaging through nail polish, which may delay the diagnosis (and worsens the prognosis)," Dr. Nazarian explains.

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Most important, however, is prevention, adds dermatologist Mona Gohara, MD. Patients should protect themselves from ultraviolet light and do monthly skin exams at home to look for any new or different lesions, including under their fingernails. If you identify a concerning spot, see an expert immediately, she says.