Check Your Skin Every Month

Skin cancer is the most commonly diagnosed cancer in the United States — more common than all other cancers combined. It is also the one most likely to be visible to the person who has it, months before anyone else notices.

That combination is unusual and worth taking advantage of. Melanoma found while still confined to the upper layers of skin has a five-year survival rate above 99 percent. Found after it has spread to distant organs, that figure drops below 40 percent. The difference between those two numbers is often measured in months of attention.

Ten minutes a month is a reasonable price for that.

The three main types

Not all skin cancers behave the same way, and knowing what you are looking for helps.

• Basal cell carcinoma is the most common. It typically appears as a pearly or waxy bump, a flat flesh-colored or brown scar-like patch, or a sore that bleeds, scabs, heals, and returns. It grows slowly and rarely spreads, but it can cause significant local damage if neglected.
• Squamous cell carcinoma often presents as a firm red nodule or a scaly, crusted, sometimes tender patch. It is more likely than basal cell to spread, particularly on the lips and ears.
• Melanoma is far less common but causes the large majority of skin cancer deaths. It can arise in an existing mole or appear as an entirely new spot, and it can spread rapidly if not caught early.

The ABCDE rule

This is the standard framework for evaluating a mole, and it is genuinely useful.

1. A — Asymmetry. One half does not match the other.
2. B — Border. Edges are irregular, notched, scalloped, or blurred rather than cleanly defined.
3. C — Color. More than one shade, or unusual colors — black, blue, red, or white patches within a brown spot.
4. D — Diameter. Larger than about six millimeters, roughly a pencil eraser. Melanomas can be smaller, so do not use this to dismiss a suspicious spot.
5. E — Evolving. Any change in size, shape, color, or elevation, or new bleeding, itching, or crusting. This is the single most important letter.

The ugly duckling sign

Alongside ABCDE, dermatologists use a simpler heuristic that is often more sensitive. Most people's moles resemble one another, like siblings. Watch for the one that does not fit the family pattern — darker, larger, differently shaped, or standing out from everything else on your body. That outlier deserves attention regardless of whether it meets any ABCDE criterion.

How to do the exam

Do it once a month, in good light, after a shower. Use a full-length mirror and a hand mirror. Pick a consistent date so it actually happens.

1. Face, ears, and neck. Include the nose, lips, and in front of and behind the ears. Use a comb or hair dryer to part hair and examine the scalp section by section — the scalp is one of the most frequently missed sites.
2. Hands and arms. Palms, backs of hands, between the fingers, under the fingernails, then forearms and upper arms, rotating to see all sides. Check the underarms.
3. Torso. Chest and abdomen. If you have breasts, lift to check underneath.
4. Back and buttocks. Turn your back to the full-length mirror and use the hand mirror. This is where a partner genuinely helps — the back is the most common melanoma site in men, and also the hardest area to see.
5. Legs. Front and back of thighs and calves, plus the backs of the knees.
6. Feet. Tops, soles, between the toes, and under the toenails.

Do not skip the areas that never see the sun. Acral lentiginous melanoma occurs on palms, soles, and under nails, and is the most common melanoma subtype among people with darker skin tones. A dark streak under a fingernail or toenail that is not explained by an injury should always be evaluated.

An important note about skin tone

Skin cancer is less common in people with darker skin, but outcomes are consistently worse — largely because diagnosis comes later. Melanoma in Black and Hispanic patients more often appears on the soles, palms, under nails, and in the mouth, and is frequently missed by patients and clinicians looking only at sun-exposed areas. Everyone, regardless of complexion, should be checking.

Track what you find

Memory is unreliable across a month. Take photographs of any spot you are watching, with a ruler or coin beside it for scale, and use consistent lighting. A change you would never notice by recall becomes obvious in a side-by-side comparison.

When to call a dermatologist

Make an appointment for any of the following:

• A spot that meets one or more ABCDE criteria
• A mole that looks different from all your others
• A sore that has not healed within three to four weeks, or that heals and reopens
• A spot that bleeds, itches persistently, or is tender without cause
• A new pigmented streak under a nail
• Any spot that has changed noticeably in recent months

Bring your photographs. Documented change over time is clinically valuable information, and it makes the visit more efficient.

Who should have professional skin exams

Routine annual dermatologic screening is generally recommended for people at elevated risk: a personal or family history of melanoma, more than 50 moles, atypical or dysplastic moles, fair skin that burns easily, significant history of sunburns or indoor tanning, organ transplant recipients and others on immunosuppressive therapy, and anyone with prior skin cancer.

Prevention still does most of the work

Detection matters, but preventing damage matters more. Ultraviolet exposure is the dominant modifiable risk factor.

• Use broad-spectrum SPF 30 or higher daily on exposed skin, and reapply every two hours outdoors or after swimming or sweating. Most people apply roughly a quarter of the amount used in testing — about a shot glass covers an adult body.
• Seek shade between 10 a.m. and 4 p.m., when UV intensity peaks.
• Wear protective clothing — a wide-brimmed hat, sunglasses, and UPF-rated fabric outperform sunscreen for sustained outdoor time.
• Never use tanning beds. Indoor tanning before age 35 raises melanoma risk substantially, and there is no safe version.
• Do not rely on cloud cover. A large share of UV radiation penetrates clouds, and it reflects off water, sand, concrete, and snow.
• Remember windows. Glass blocks UVB but transmits UVA, which contributes to aging and cancer risk — relevant for anyone who drives a lot.

None of this requires avoiding the outdoors. Middle Tennessee summers are meant to be spent outside. It requires only that the habits become automatic — sunscreen by the door, a hat in the car, and one recurring reminder each month to spend ten minutes in front of a mirror.

Dermatology specialists at Vanderbilt Health provide skin cancer screening, diagnosis, and treatment, including surgical and medical management of melanoma and non-melanoma skin cancers, with coordinated care for patients who need it.

This article is for general education and is not a substitute for professional medical advice. To schedule dermatology care at Vanderbilt Health, call (615) 343-4444 or (800) 288-5000.