Many people aren’t aware that those with darker skin are at risk of skin cancer, let alone melanoma under the nails. Anyone can get subungual melanoma, but it’s most common in people with dark skin and older people. This rare but serious type of melanoma can be easily missed.

Nail melanoma is usually a form of acral lentiginous melanoma, which develops from the skin on the hands and feet. It’s important to know the signs of subungual melanoma and check your nails regularly. Subungual melanoma is very treatable if it’s caught early.

Learn more about nail melanoma, including signs and symptoms to look for, risk factors for developing nail melanoma, and when it’s time to see a doctor.

What Is Subungual Melanoma?

Like other types of melanoma, subungual melanoma develops in melanocytes, the pigment cells that give skin its color. Unlike most types of skin cancer, subungual melanoma isn’t related to sun exposure. Nail melanoma often shows up as a narrow brown or black streak or band on the nail. The streaks result when melanocytes make too much of the skin pigment melanin.

Scientists don’t know the exact cause of nail melanoma, but this increased production of melanin has been linked to nail melanoma.

Signs and Symptoms of Subungual Melanoma

Subungual melanoma most often appears as a brown or black vertical line, typically on a thumbnail or nail of a big toe. The line is usually less than 3 millimeters wide but can widen over time, starting at the bottom of the nail.

It’s important to note that people of color may have streaks in their nails that aren’t a sign of cancer. These normal variations usually affect more than one nail and don’t change over time.

Another key symptom of subungual melanoma is Hutchinson’s sign. Hutchinson’s sign refers to discolored skin just below and beside the nail. However, Hutchinson’s sign doesn’t always mean melanoma is present.

Nail Melanoma: What To Watch For

It’s important to be vigilant about checking for warning signs of subungual melanoma because melanoma is highly treatable when caught early. According to the American Academy of Dermatology, you should watch out for these key nail changes:

• A brown or black streak, usually on the thumbnail or big toe nail of your dominant hand or foot
• A colored band on your nail, either narrow and dark or wide and irregular
• A nodule or bump underneath the nail
• Darker skin around your nail (Hutchinson’s sign)
• A split down the middle of a nail
• Nails that lift or separate from the nail bed (skin underneath the nail)

Although a dark band is often a key clue to subungual melanoma, sometimes the nail doesn’t show any discoloration. This is why it’s important to look for any abnormal nail changes. For example, nails affected by subungual melanoma might also be painful or thin, deformed, and cracked.

Risk Factors for Subungual Melanoma

Subungual melanoma accounts for less than 1 percent to 4 percent of all melanoma cases, but it’s the most common type in people with dark skin. Although it can occur in people of all skin tones and racial/ethnic backgrounds, subungual melanoma is more common among people of African-American, Asian, and Hispanic descent. For example, nail melanoma accounts for up to 75 percent of melanomas in dark-skinned and Asian populations.

Subungual melanoma is also more common in older people than younger people, usually affecting people aged 60 to 70 years old.

Other risk factors for subungual melanoma include having:

• Many moles or freckles
• Light skin and hair
• A family history of melanoma or other forms of skin cancer
• A weakened immune system because of a health condition
• A prior injury to the affected nail

Nail Conditions That Resemble Subungual Melanoma

A dark band or streak that indicates subungual melanoma can look like a bruise under the nail, so it may be mistaken for an injured nail. However, a bruise will go away, while a dark streak caused by subungual melanoma will stay and may even grow.

Nail melanoma might also be mistaken for a nail infection because some symptoms overlap. For example, a fungal nail infection can cause color and texture changes. However, infected nails may appear green or yellow, unlike the brown or black streak suggesting subungual melanoma.

When It’s Time To See a Doctor

Talk to your doctor or dermatologist if you notice changes to the nail that get worse or don’t go away so that you get an accurate diagnosis and treatment, if needed. Tell your health care provider if you notice that your nail changed in shape, color, or texture (like dents or changes in thickness) and if the nail separates from the nail bed.

Tests To Diagnose Subungual Melanoma

Your doctor may do testing to rule out other causes of these nail changes. They’ll look at your nails and ask how long you’ve had these symptoms and if they’ve changed over time. They may also ask about your family’s health history as well as yours.

If your doctor thinks that subungual melanoma might be causing the nail changes, they’ll likely take a biopsy by collecting a small sample of the affected nail. If studying the cells under a microscope confirms a subungual melanoma diagnosis, your doctor may order more tests to determine if and how the cancer has progressed or spread to other parts of the body.

Prognosis With Subungual Melanoma

Some studies have shown a worse prognosis (outlook) for subungual melanoma compared to skin melanoma. However, this is likely because subungual melanoma can be hard to catch early on, so the prognosis might actually be similar for nail and skin melanomas.

If subungual melanoma is caught in the early stage and treated right away, scientists estimate the survival rate to be about 95 percent, according to Cleveland Clinic. The survival rate can drop to as low as 15 percent if subungual melanoma goes undiagnosed for a long time and spreads to other parts of the body. This shows how important it is to know the signs of subungual melanoma for early detection.

Treatment for Subungual Melanoma

Subungual melanoma treatment often means surgical removal of the affected area or the whole nail, sometimes along with part of the finger. If the cancer has spread to other parts of the body, immunotherapy and other cancer treatments like chemotherapy and radiation therapy may also be needed to fight the melanoma.

Your doctor will come up with a treatment plan based on your overall health and stage of melanoma so that you have the best chance at successful treatment.

Talk With Others Who Understand

MyMelanomaTeam is the social network for people with melanoma and their loved ones. On MyMelanomaTeam, members come together to ask questions, give advice, and share their stories with others who understand life with melanoma.

Have you been diagnosed with nail melanoma? What symptoms do you have? Share your experience in the comments below, or start a conversation by posting on your Activities page.