If you’ve ever had your skin examined by a dermatologist, you know the drill: Prepare for a study that focuses on parts of your body you never think about, much less expose to the sun. Although most people associate skin cancer with sunbathing, tanning beds, and/or incorrect application of sunscreen, it turns out that many skin cancers occur without the help of the sun and its powerful UV rays.
“Skin cancer can be sneaky,” says Alix Charles, a board-certified dermatologist in Hinsdale, Illinois. In fact, the worst cases of skin cancer usually develop in areas where the sun does not usually shine; places that, if left undetected, can lead to delayed diagnosis, more invasive treatment, and more serious cases of cancer.
Here’s why dermatologists want you to redefine the relationship you have with your skin, especially in its most secret corners.
Skin cancer can occur in various forms, most of them associated with years of exposure to ultraviolet radiation from the Sun. This hits the Earth’s surface, passing through our atmosphere and putting human skin at risk of cancer.
Most of the harmful UV radiation is received between 10 a.m. and 4 p.m., when the sky is brightest. But the human eye cannot detect UV rays, which have shorter wavelengths than visible light, and can damage skin even on cloudy days. Excessive UV exposure is associated with the two most common forms of skin cancer, basal cell carcinoma and squamous cell carcinoma. Although genetics play a role in both types of cancer, UV exposure does not help; instead, it damages the DNA of skin cells, increasing the risk of mutations as the body attempts to repair the damage.
According to the American Academy of Dermatology, about 5.4 million cases of basal and squamous cell carcinoma are detected in the United States each year. But although severe cases of both cancers can be fatal, they are much less dangerous than melanomas, an invasive form of skin cancer that is not always caused by UV exposure. Melanomas are associated with uncontrolled cell growth that occurs with various genetic mutations. In Spain, 78,000 cases of skin cancer are diagnosed each year (of which more than 74,000 are non-melanoma skin cancer and 4,000 are melanoma).
This more invasive form of cancer can sometimes be caused by intense UV exposure, but inherited and acquired genetic mutations and a weakened immune system are also thought to contribute. And unlike their slow-growing counterparts, melanomas can spread, forming new tumors in other parts of the body as the aggressive cancer passes through the lymph system and bloodstream.
Dermatologists like Charles say it’s essential to monitor the health of your skin, even in the less intuitive areas that don’t get much sun.
“There is almost always an opportunity to visually detect skin cancer,” Charles says, even in places where most people wouldn’t think to check. These are some of the main suspects:
Fingernails and toenails: “The great Bob Marley died of melanoma that started under his toenail,” says Charles. Known as subungual melanomas, cancers that form under the nails usually present in the form of dark, vertical brown-black streaks that appear most frequently on the skin under the nail of the big toe, thumb or index finger. Although relatively rare, these melanomas are the most common type of malignant melanoma among black, Asian, and Hispanic patients.
Ears: The ears are very exposed to the sun. But they also harbor darker corners that can easily hide serious and severe cancers. However, due to the unique shape of the ears, skin cancers in the crevices of the ears are easy to miss, and late diagnosis is common among many patients.
The eyes: Although rare, some cases of skin cancer can develop inside the eye. Dark spots may appear on the iris or white part of the eye, and skin cancer may also appear on the eyelid. Merkel cell carcinoma, a rare cancer of a specific type of cells in the top layer of the skin, usually presents as a small, firm lump on the eyelid. It is one of the most aggressive types of cancer, with a mortality rate of 40% and a high recurrence rate.
The genitals: It may be embarrassing to ask about a suspicious lesion in the groin area, but skin cancer can even appear on the skin over the vulva and penis or inside the vagina and cervix. “I once had a patient who was embarrassed to ask me to look at a spot in her genital region that was changing,” says Charles. “It turned out that she had an atypical vulvar lesion that was skin cancer. Most women don’t think to check their own vulvar area, but skin cancer can appear there.” Although the sun does not shine on these sensitive areas, skin cancer formation there usually follows the course of the most exposed regions, often with mole-like lesions that change over time.
The feet: Skin cancer can also appear on the soles of the feet, and the American Academy of Dermatologists warns that, for people of African and Asian ethnicity, the feet and hands are the most common areas of melanoma. Patients should check between the toes, on the soles of the feet, and along the top and sides of each foot.
The scalp: You may put sunscreen on your face when you go out, but do you forget about the hair part? Big mistake, says Charles, who routinely detects skin cancers on the scalps of his patients. Although melanoma of the scalp is more common in patients with bald spots or thinning hair, it can also be hidden under thick hair. That’s why dermatologists recommend making sure you’ve applied sunscreen before going outside.
The long list of places contraindicated for skin cancer may seem alarming, but Charles says that, thanks to friends, savvy partners, and trained dermatologists, it’s surprisingly easy to spot most skin cancers.
“Give credit to your partner, your spouse, and your friends: They can literally watch your back,” she says. If you spot an area of concern, see a dermatologist as soon as possible. “The earlier a skin cancer is detected and treated, the better the prognosis, the smaller the scar and the less likely it is that the cancer has spread to a distant area,” says Charles.
To know if a skin spot should be cause for concern, the American Academy of Dermatologists recommends following the “ABCDE Rule.” If you have a stain that presents tosymmetry, a bpoorly defined order, cvariable odor, a ddiameter greater than 6 mm or a andevolution and change over time, it’s time to call your doctor. If you have a family history of skin cancer, a history of frequent sunburns, or a light skin tone, you may want to schedule regular skin checkups with a dermatologist.
But everyone should check their skin regularly, Charles says, even those with a darker skin tone. “If you’re not sure, it never hurts to see a dermatologist to evaluate your risk,” he says. Your doctor’s thoroughness may inspire you to keep a closer eye on the darker areas of your body, just in case.