What Is Subungual Melanoma?

Signs and Symptoms of Subungual Melanoma

Wrinkled Hands
Wrinkled Hands. Nurcholis Anhari Lubis / Stringer / Getty Images

Subungual melanoma is a specific type of melanoma that occurs under the nail bed more commonly in dark-skinned people.

What is Melanoma?

Melanoma, the most serious type of skin cancer, develops in the cells (melanocytes) that produce melanin — the pigment that gives your skin its color. Melanoma can also form in your eyes and, rarely, in internal organs, such as your intestines.

Causes of Melanoma

Melanoma occurs when something goes awry in the melanin-producing cells (melanocytes) that give color to your skin.

Normally, skin cells develop in a controlled and orderly way — healthy new cells push older cells toward your skin's surface, where they die and eventually fall off. But when some cells develop DNA damage, new cells may begin to grow out of control and can eventually form a mass of cancerous cells.

Just what damages DNA in skin cells and how this leads to melanoma isn't clear. It's likely that a combination of factors, including environmental and genetic factors, causes melanoma. Still, doctors believe exposure to ultraviolet (UV) radiation from the sun and from tanning lamps and beds is the leading cause of melanoma.

UV light doesn't cause all melanomas, especially those that occur in places on your body that don't receive exposure to sunlight. This indicates that other factors may contribute to your risk of melanoma.

Risk Factors For Melanoma

Factors that may increase your risk of melanoma include:

  • Fair skin. Having less pigment (melanin) in your skin means you have less protection from damaging UV radiation. If you have blond or red hair, light-colored eyes, and freckle or sunburn easily, you're more likely to develop melanoma than is someone with a darker complexion. But melanoma can develop in people with darker complexions, including Hispanics and blacks.
  • A history of sunburn. One or more severe, blistering sunburns can increase your risk of melanoma.
  • Excessive ultraviolet (UV) light exposure. Exposure to UV radiation, which comes from the sun and from tanning lights and beds, can increase the risk of skin cancer, including melanoma.
  • Living closer to the equator or at a higher elevation. People living closer to the earth's equator, where the sun's rays are more direct, experience higher amounts of UV radiation than do those living in higher latitudes. In addition, if you live at a high elevation, you're exposed to more UV radiation.
  • Having many moles or unusual moles. Having more than 50 ordinary moles on your body indicates an increased risk of melanoma. Also, having an unusual type of mole increases the risk of melanoma. Known medically as dysplastic nevi, these tend to be larger than normal moles and have irregular borders and a mixture of colors.
  • A family history of melanoma. If a close relative — such as a parent, child or sibling — has had melanoma, you have a greater chance of developing a melanoma, too.
  • Weakened immune system. People with weakened immune systems, such as those who've undergone organ transplants, have an increased risk of skin cancer.

Subungual Melanoma

Subungual melanoma causes a dark colored stripe that runs along the length of the nail plate, not across the nail. Just having a dark nail stripe is not necessarily melanoma. The following signs make it more likely that a dark stripe is a subungual melanoma and should be evaluated by a dermatologist:

  • Hutchinson's Sign - Spread of pigmentation into the nail folds
  • Pigmentation in a single digit
  • Occurs at age 50 or older
  • Occurs in the thumb, index finger, or great toe
  • Blurred borders
  • History of melanoma


Mayo Clinic. Melanoma. http://www.mayoclinic.org/diseases-conditions/melanoma/basics/definition/con-20026009

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