What can skin cancer look like?

What it is

Skin cancer includes several diseases arising from different skin cells. Appearance varies by type, body location, skin tone and stage. Comparing your lesion with one online photograph is unreliable because benign moles, cysts, eczema and sun spots can resemble cancer—and cancers can initially look harmless.

Use appearance guides to recognize reasons to book an exam, not to rule cancer in or out. RashScan does not diagnose skin cancer. A dermatologist can examine the whole lesion, use dermoscopy and arrange a biopsy when needed.

What it looks and feels like

• Melanoma: a new or changing pigmented spot, asymmetry, irregular border, varied color, increasing diameter or evolution.
• Basal cell carcinoma: a shiny or pearly bump, pink growth, scar-like area or sore that bleeds and returns.
• Squamous cell carcinoma: a rough scaly patch, firm red growth, crusted lesion or non-healing ulcer.
• Across all types: change, unexplained bleeding, persistent crusting, pain or failure to heal are important clues.
• On nails or acral skin: a new dark streak or changing spot on palms, soles or under a nail warrants review.

Causes, triggers and risk factors

• Ultraviolet exposure from sunlight or tanning beds.
• Fair skin, light eyes or hair, but every skin tone can develop skin cancer.
• Many or atypical moles, personal or family history of melanoma.
• Immune suppression, previous radiation or certain chronic wounds.
• Age and cumulative sun exposure, while melanoma can also occur in younger adults.

Treatment and self-care

Do not self-treat a suspicious lesion with acids, freezing products or online “mole removers.” Treatment depends on the diagnosis and may include surgical removal, topical prescription therapy, radiation or systemic treatment. Early evaluation generally allows simpler treatment.

Prevention includes broad-spectrum SPF 30+ sunscreen, shade, protective clothing, avoiding tanning beds and checking your skin regularly. Photograph a lesion only to document change; do not let monitoring delay an appointment.

Conditions that can look similar

• Seborrheic keratosis: waxy or “stuck-on” benign growths that can still need confirmation.
• Actinic keratosis: rough sun-damaged patch that is precancerous and should be assessed.
• Dermatofibroma: firm benign bump, often on a leg.
• Eczema or psoriasis: scaly patches, usually with a broader pattern or history.
• Trauma or infection: sores should heal predictably; persistence is the warning sign.

The ABCDE and “ugly duckling” checks

A—Asymmetry: one half differs from the other. B—Border: edges are irregular, notched or blurred. C—Color: multiple colors or uneven distribution. D—Diameter: larger lesions can be concerning, but melanoma may be smaller than 6 mm. E—Evolving: any meaningful change over time.

The “ugly duckling” approach compares a spot with your own mole pattern. A lesion that looks unlike the rest can be important even if it does not satisfy every ABCDE feature. On darker skin, melanoma is proportionally more likely to be found on palms, soles or under nails and may be diagnosed later, making awareness especially important.

When to see a healthcare professional

• A spot changes in size, shape, color, surface or symptoms.
• A sore does not heal within several weeks, or repeatedly bleeds and crusts.
• A pigmented lesion is an “ugly duckling” unlike your other moles.
• There is a new dark streak under a nail without clear injury.
• A lesion is rapidly growing, painful, ulcerated or associated with a new lump.

Sources and further reading

We use established public-health and dermatology references and link them directly so you can verify the guidance and read further.

• Skin cancer: signs and symptoms — American Academy of Dermatology
• Skin cancer — National Cancer Institute

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