Nearly 100,000 Americans are diagnosed with melanoma each year, making it one of the most common types of cancer in the U.S., especially among older adults who have endured decades of sun exposure and whose immune systems aren't as robust as they once were. And while melanoma can be deadly, it is highly curable if caught early.

Melanoma usually presents as asymmetrical or rough-looking moles that aren't defined by a border. A spot on the skin that continues to grow in size or change is another indication, and a once-monthly body scan is an easy way to keep track of any of these concerning characteristics. However, there are also some more unusual signs that could signal the presence of the skin cancer.

“Melanoma is such a rule breaker,” says Elizabeth Buchbinder, M.D., an oncologist at the Dana-Farber Cancer Institute in Boston and an assistant professor at Harvard Medical School told AARP in the article titled “4 Warning Signs of Melanoma That Are Easy to Miss.” The doctor notes that “little moles can cause big trouble, and new spots can grow and spread quickly, and so knowing what to look out for, it's super important.” AARP gives us four warning melanoma signs to know about so no spot goes unnoticed.

1. The “Ugly Duckling.” Folks with a lot of moles are at increased risk for melanoma, but don't start counting your spots or panicking over every mark on your body. Rather, you should pay attention to the moles that stand out — those that are darker than the rest, have changed recently or are more oddly shaped. The doctor calls these “ugly ducklings.”

“If you have a bunch of dark moles, but you have 50 of them, they're not all melanomas,” Dr. Buchbinder says. “But if you have one mole that really looks different than the others, and it's kind of that ugly duckling, that's the one that you really want to get looked at and checked.”

1. “Where the sun don't shine.” Most melanomas are thought to be caused by ultraviolet (UV) light. However, not all of them come from sun exposure. Melanoma can develop anywhere on the body, including in places where the sun doesn't shine—the soles of your feet or the palms of the hand. It can also appear as a dark streak under a fingernail or toenail. Although it's rare, melanoma can also develop on the eye, inside the mouth, or on the scalp.
2. Red, white, and blue hues. This cancer is often depicted as dark-brown moles, but it can actually present in a variety of colors. The cancer may have a blue tint to it, from deeper pigmentation, or it can appear red, the result of an immune response. In addition, melanoma can also look like a rash and take on a pink hue. When the spot doesn't get better with creams and other treatments that normally treat a rash, go see your doctor. Another sign of a melanoma can be lack of color. Some of these cancerous spots lose their pigmentation completely or partially, leaving a halo of white around a darker spot.
3. Bleeding or Itching Skin Spots. If a mole on your body starts to itch or becomes more painful or tender, go see a doctor. Likewise, if the surface of a mole changes, such as oozing or bleeding, or if it becomes scalier and doesn't heal on its own.

Preventing Melanoma. You should wear sun-protective clothing and UV-blocking sunglasses, and use plenty of sunscreen to help prevent melanoma. Plus, those on certain blood pressure medications, including diuretics such as hydrochlorothiazide and calcium channel blockers such as nifedipine, for example, need to be extra cautious when spending time outside. However, because not all skin cancers are caused by sun exposure, frequent skin checks are also a critical role in prevention.

Reference: AARP (July 9, 2021) “4 Warning Signs of Melanoma That Are Easy to Miss”