Skin cancer is, by raw case count, the most common cancer diagnosed in the United States — yet it’s also among the most preventable and, when caught early, among the most treatable. The gap between those two facts comes down almost entirely to early detection, which means understanding what to actually look for, how often professional screening makes sense, and what happens if a dermatologist finds something concerning.

The Three Main Types and Why the Distinction Matters

Basal cell carcinoma is the most common form, typically appearing as a pearly or waxy bump, a flat flesh-colored lesion, or a sore that doesn’t heal. It grows slowly and rarely spreads (metastasizes) to other parts of the body, making it highly treatable, though left untreated it can cause significant local tissue damage, particularly concerning on the face where many cases occur.

Squamous cell carcinoma often presents as a firm, red nodule or a flat lesion with a scaly, crusted surface, and while still highly treatable when caught early, it carries a somewhat higher risk of spreading compared to basal cell carcinoma, particularly in immunocompromised patients or lesions on the ears, lips, or genitals.

Melanoma, while far less common than the other two types, accounts for the large majority of skin cancer deaths because of its significantly higher tendency to metastasize if not caught early. This is precisely why melanoma screening and self-examination protocols (the ABCDE rule, covered below) focus so heavily on catching changes in moles and pigmented lesions specifically — early-stage melanoma has excellent survival rates, while advanced, spread melanoma is considerably harder to treat.

The ABCDE Rule for Self-Examination

Dermatologists commonly teach the ABCDE framework as a practical, memorable way to evaluate moles and pigmented spots during self-checks. Asymmetry — one half of the mole doesn’t match the other half — is a warning sign, since benign moles are typically symmetrical. Border irregularity, where edges are ragged, notched, or blurred rather than smooth, is another red flag, as is Color variation within a single mole (multiple shades of brown, black, or even red, white, or blue) rather than uniform coloring.

Diameter exceeding roughly 6mm (about the size of a pencil eraser) warrants attention, though it’s worth noting melanomas can occasionally be smaller, so diameter alone shouldn’t be the sole deciding factor. Evolving — any change in size, shape, color, elevation, or new symptoms like itching, bleeding, or crusting in an existing mole — is often considered the single most important sign, since change over time is frequently the clearest indicator something needs professional evaluation regardless of how the mole scores on the other criteria.

A useful practical habit is the “ugly duckling” sign — looking for any mole that simply looks notably different from the person’s other moles, since most people’s benign moles tend to share a similar general appearance, making genuine outliers worth professional attention even if they don’t clearly meet every ABCDE criterion.

Risk Factors Worth Understanding

Ultraviolet exposure remains the single most significant modifiable risk factor across all skin cancer types, whether from sun exposure or tanning bed use — the World Health Organization classifies tanning beds as a known human carcinogen, and even a small number of tanning bed sessions, particularly before age 35, measurably increases melanoma risk.

Fair skin, light eye color, and a tendency to burn rather than tan are associated with higher risk given lower natural melanin protection. A personal or family history of skin cancer, particularly melanoma, substantially increases risk and generally warrants more frequent professional screening than the general population baseline. A high total mole count, or the presence of atypical (dysplastic) moles specifically, also correlates with elevated risk and often prompts more frequent dermatological monitoring.

Immunosuppression — whether from organ transplant medications, certain autoimmune treatments, or conditions like HIV — significantly increases skin cancer risk and generally warrants more frequent specialist screening, since the immune system plays a meaningful role in identifying and controlling abnormal cell growth.

How Often Should You See a Dermatologist?

For the general population without significant risk factors, an annual full-body skin exam by a dermatologist is a commonly recommended baseline, though guidelines aren’t perfectly uniform across medical organizations. For higher-risk individuals — significant personal or family history, high mole count, immunosuppression, or a previous skin cancer diagnosis — more frequent screening, sometimes every three to six months, is often recommended by the treating dermatologist based on individual risk profile.

Between professional visits, monthly self-examination using the ABCDE framework, ideally with the help of a partner or photos for hard-to-see areas like the back and scalp, helps catch changes between formal appointments — skin cancer detected by patients themselves between visits is a meaningful share of diagnoses, underscoring that self-vigilance genuinely matters alongside professional screening rather than being a redundant precaution.

What Actually Happens During a Skin Cancer Screening

A standard full-body skin exam involves a dermatologist visually inspecting the skin from head to toe, including areas people often overlook themselves like the scalp, between toes, and the back. Many dermatologists use dermoscopy — a specialized magnifying tool with polarized light — to examine concerning lesions more closely, since certain structural features visible under dermoscopy can help distinguish benign moles from those warranting biopsy, sometimes avoiding unnecessary biopsies for clearly benign-appearing lesions.

If a lesion appears concerning, a biopsy is typically performed during the same visit or scheduled shortly after — a relatively quick, minor procedure under local anesthesia removing all or part of the lesion for laboratory analysis. Results typically take one to two weeks, and the dermatologist will discuss treatment options based on the specific diagnosis and stage if cancer is confirmed.

Treatment Approaches by Type and Stage

For most basal and squamous cell carcinomas caught early, surgical excision — removing the lesion along with a margin of healthy surrounding tissue — is highly effective, often performed in-office under local anesthesia. Mohs surgery, a specialized technique involving sequential removal and immediate microscopic examination of tissue layers, is often used for cancers in cosmetically or functionally sensitive areas (face, ears, hands) since it allows for maximum preservation of healthy surrounding tissue while ensuring complete cancer removal.

Early-stage melanoma treatment similarly centers on surgical excision with appropriate margins based on tumor thickness, sometimes combined with sentinel lymph node biopsy to check whether the cancer has begun spreading. More advanced melanoma may involve additional treatments including immunotherapy or targeted therapy, reflecting the significant treatment advances in melanoma care over the past decade that have meaningfully improved outcomes even for more advanced cases compared to historical treatment options.

Prevention Beyond Sunscreen

While daily broad-spectrum sunscreen (SPF 30 or higher) remains foundational, comprehensive sun protection includes seeking shade during peak UV hours (typically 10am-4pm), wearing UV-protective clothing and wide-brimmed hats for extended outdoor exposure, and avoiding tanning beds entirely given their established carcinogenic risk. Reapplying sunscreen every two hours during extended outdoor exposure, and after swimming or sweating, matters significantly more than people often realize, since a single morning application rarely provides adequate protection through a full day outdoors.

Frequently Asked Questions

Can skin cancer occur in areas never exposed to sun? Yes, though less commonly — skin cancer can occur on covered areas, soles of feet, palms, and even under nails, which is part of why a comprehensive professional exam covers the entire body rather than just sun-exposed areas.

Is a biopsy painful? Most skin biopsies are performed under local anesthesia and involve minimal discomfort during the procedure, with some soreness at the site for a few days afterward as it heals.

Does having many moles automatically mean higher cancer risk? A higher mole count is associated with somewhat elevated statistical risk, but the vast majority of moles, even in people with many of them, remain entirely benign — the key is monitoring for change rather than assuming a high mole count itself is dangerous.

Is skin cancer screening typically covered by insurance? Routine skin cancer screening exams are generally covered, particularly when there’s a documented risk factor or family history, though coverage specifics vary by plan and it’s worth confirming whether the visit will be billed as preventive or diagnostic, which can affect cost-sharing.

The Bottom Line

Skin cancer’s combination of high prevalence and high treatability when caught early makes consistent screening — both professional and self-examination — one of the more straightforwardly valuable health habits available. Understanding the ABCDE warning signs, knowing your personal risk factors, and maintaining a screening schedule appropriate to that risk level meaningfully improves the odds of catching anything concerning while it’s still highly treatable, rather than after it’s had time to progress.

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