Causes and Risk Factors
Melanoma results from DNA damage in pigment cells, most often driven by ultraviolet (UV) exposure. According to the American Cancer Society, important risk factors include:- UV exposure and sunburns: Intense, intermittent sun exposure and blistering sunburns — especially in childhood — raise lifetime risk, as does any tanning bed use.
- Many or unusual moles: Having more than 50 moles, or moles that are large and irregular (atypical nevi), increases risk.
- Fair skin, freckling, and light hair: Melanoma can occur in any skin tone, but risk is highest in fair-skinned people.
- Family or personal history: A close relative with melanoma, or a prior melanoma of your own, calls for regular professional skin checks.
- A weakened immune system: Immune-suppressing medications and conditions such as chronic leukemia or lymphoma reduce the body's ability to repair and remove damaged cells.
Symptoms
Melanoma usually appears as a new dark spot or a changing mole. The ABCDE rule summarizes the warning signs:- A — Asymmetry: One half of the spot does not match the other.
- B — Border: Edges are ragged, notched, or blurred.
- C — Color: Multiple shades of brown, black, red, white, or blue within one spot.
- D — Diameter: Larger than about 6 millimeters (a pencil eraser), though melanomas can be smaller.
- E — Evolving: Any change in size, shape, color, or symptoms such as itching or bleeding.
- The ugly duckling sign: A mole that looks or feels different from all your others deserves attention, even if it does not fit the letters above.
Diagnosis
A clinician inspects the spot, often with a lighted magnifier called a dermatoscope, and removes suspicious lesions for biopsy. Not every changing spot is cancer — irritated moles and inflamed patches of dermatitis are common mimics — but only a biopsy can say for certain. If melanoma is confirmed, its depth guides whether nearby lymph nodes should also be checked. Melanoma can also develop under a nail, on the soles of the feet, or in other rarely sun-exposed places, so a thorough examination covers the entire skin surface.Treatment
Early melanoma is treated with surgical removal of the lesion plus a margin of healthy skin, which is curative for most thin melanomas. Deeper or more advanced disease may require lymph node evaluation and additional therapy, including immunotherapy medicines such as pembrolizumab that help the immune system attack cancer cells. After any melanoma, lifelong skin surveillance and strict sun protection are essential, and your care team will set a follow-up schedule that is typically most frequent in the first years after diagnosis.Prevention
Daily broad-spectrum sunscreen, protective clothing and wide-brimmed hats, avoiding midday sun, and never using tanning beds meaningfully lower melanoma risk. In Florida's intense year-round sun, these habits matter for every member of the family, starting in childhood. Monthly self-checks and a yearly professional skin examination are the best insurance against a dangerous melanoma. Zimmer Medical Group's primary care team in St. Petersburg can examine changing moles promptly and coordinate rapid dermatology referral when a spot looks suspicious — schedule an appointment if something on your skin has changed.After the Biopsy: Treatment and the Years That Follow
A melanoma diagnosis sets off a sequence of decisions in the first weeks and a surveillance routine that continues for life. Knowing what the pathology report drives and what follow-up looks like takes some of the fear out of both.
What the pathology report decides
Depth in millimeters, ulceration, and how actively the cells are dividing determine the stage and nearly everything that follows. A second, wider excision removes a margin of normal skin around the biopsy site that grows with the depth of the tumor. Beyond the thinnest category, a sentinel lymph node biopsy is offered at the same operation to check whether cells have reached the nearest node. Very thin melanomas and melanoma in situ are cured by excision alone in nearly every case.
Treatment beyond surgery
Melanoma that has reached the lymph nodes or spread further is now treated with immunotherapy such as pembrolizumab, or with targeted pills for tumors carrying a BRAF mutation, and both have dramatically improved survival in advanced disease. Immunotherapy is also given after surgery to lower recurrence. Its side effects come from the immune system attacking normal tissue, most often the thyroid, causing hypothyroidism, and also the bowel, skin, and liver; new diarrhea, rash, or fatigue during treatment is reported the same day.
Follow-up for life
Skin examinations every three to six months for the first few years, then yearly, watch for both a recurrence and a second melanoma, which develops in a meaningful share of survivors. Lymph node checks are part of each visit, and imaging is added for higher stages. First-degree relatives should begin regular skin checks. Our skin cancer screening article covers the full-body exam, and the basal and squamous cell and actinic keratosis pages cover the other sun-related growths survivors are prone to.
Sun protection that survives a Florida summer
The UV index here is high most of the year, water and boat decks reflect it, and car windows block only part of it. Sunscreen is reapplied every two hours outdoors, and UPF clothing, a wide-brimmed hat, and shade between ten and four do more than any lotion. Vitamin D comes from a supplement rather than from the sun; our vitamin D in the Sunshine City article explains why. Our Florida sun safety guide and sun protection for eyes and skin article cover the details.
Self-checks and the mimics
A monthly check in good light with a mirror, and photographs of any spot in question, catch changes earlier than memory. Seborrheic keratoses, the waxy stuck-on growths that multiply after fifty, and blood under a nail from an injury are common look-alikes; our benign skin growths after 50 article shows the differences. A dark nail streak that widens or spreads onto the skin, or a spot on the sole, is examined rather than watched. Our dermatologic team coordinates urgent referral. The National Cancer Institute and the CDC publish patient guidance.
If a mole has changed, a new dark spot has appeared, or you have had a melanoma and are overdue for a skin check, schedule a visit.