Overview
What Is Skin Cancer?
Skin cancer is the uncontrolled growth of abnormal cells in the skin. The main types are basal cell carcinoma, squamous cell carcinoma, and melanoma, which begins in pigment-producing cells. These skin cancer types can look and behave differently. Skin cancer can affect people of all skin tones, including people with darker skin.
Symptoms
Skin Cancer Symptoms and Warning Signs
Common skin cancer symptoms include a new or changing spot, a sore that does not heal, bleeding or crusting, or a pearly, shiny, or scaly growth. A mole that changes in size, shape, or color should also be checked. Itching, pain, or tenderness can occur, but skin cancer does not always cause these symptoms. Because appearance alone cannot confirm a diagnosis, concerning skin cancer spots need professional assessment.
- Asymmetry: One half of the spot does not match the other half.
- Border changes: The border becomes uneven, notched, blurred, or poorly defined.
- Color variation: The spot contains different shades of brown, black, red, white, or blue.
- Diameter or size change: A spot grows or becomes larger than it was previously.
- Evolution over time: The lesion changes in appearance, symptoms, or texture.
- Ugly duckling sign: A spot looks noticeably different from the person’s other moles.
IMPORTANT
Do not diagnose from photographs
Online photographs cannot reliably determine whether a lesion is cancerous. Arrange a dermatology evaluation for any persistent, unusual, bleeding, or changing lesion, including one on the face or another sun-exposed area.
Causes
What Causes Skin Cancer?
Skin cancer develops when accumulated damage to DNA causes skin cells to grow and divide abnormally. Ultraviolet radiation from sunlight and tanning beds is a major contributor, while inherited traits, age, immune health, and other environmental factors can also influence risk. Over time, damaged cells may escape the body’s usual growth controls.
How ultraviolet radiation damages skin cells
Ultraviolet radiation can injure the DNA of skin cells and contribute to basal cell skin cancer, squamous cell carcinoma, and melanoma skin cancer. The body repairs much of this damage, but repeated or severe injury can allow abnormal changes to build up. Skin cancer is not contagious, and it can occur even when there is no single obvious cause.
Risk Factors
Skin Cancer Risk Factors
- Frequent or intense ultraviolet exposure from sunlight or tanning beds increases cumulative skin damage.
- A history of sunburns, especially blistering burns, is associated with higher risk.
- Many moles, atypical moles, or a personal or family history of skin cancer can increase risk.
- Fair skin, light eyes, light hair, or a tendency to freckle or burn can increase susceptibility to ultraviolet damage.
- A weakened immune system or certain immune-suppressing medicines can reduce the body’s ability to control abnormal cells.
- Older age or prior radiation exposure can increase risk in some people.
Side Effects & Complications
Skin Cancer Complications and Treatment Side Effects
Untreated skin cancer can invade nearby tissue, cause ulceration or bleeding, and disfigure the skin. In some cases, it can spread to lymph nodes or distant organs; melanoma carries the greatest metastatic risk among the common types. Treatment can also cause effects that vary by procedure, location, cancer type, and overall health.
Possible effects of treatment
Surgery may result in pain, scarring, infection, pigment changes, or wound-healing problems. Radiation therapy can cause skin irritation and other local reactions. Immunotherapy and targeted therapy may cause systemic effects, so patients should report new or worsening symptoms to their treatment team.
WHEN TO CALL
Report concerning treatment changes
Contact your treatment team for rapidly worsening pain, fever, uncontrolled bleeding, changes in a wound, or new symptoms during therapy. Seek urgent care when symptoms are severe or rapidly progressing.
Diagnosis & Staging
How Skin Cancer Is Diagnosed and Staged
Diagnosis begins with a skin examination and, when appropriate, an examination of nearby lymph nodes. Confirmation requires removing part or all of the suspicious lesion in a biopsy for laboratory examination by a pathologist. A clinician may also recommend additional tests based on the suspected cancer type and examination findings.
What a biopsy and stage can show
A biopsy report may identify the cancer type, depth or thickness, margins, growth features, and other characteristics that guide treatment. Staging describes how extensive the cancer is, including whether it remains local, involves lymph nodes, or has spread to distant organs. Skin cancer pictures or images can raise concern, but they cannot replace biopsy and pathology.
| Cancer type | What staging commonly considers |
|---|---|
| Melanoma | Tumor thickness, ulceration, lymph nodes, and distant spread |
| Basal cell or squamous cell carcinoma | Tumor size, depth or local invasion, high-risk features, lymph nodes, and distant spread when applicable |
Treatment Options
Skin Cancer Treatment Options
Local treatments and surgery
Radiation therapy
Systemic therapy
Prevention
How to Prevent Skin Cancer
- Seek shade and avoid intense midday sunlight when possible.
- Wear tightly woven protective clothing, a wide-brimmed hat, and UV-blocking sunglasses.
- Use broad-spectrum, water-resistant sunscreen with SPF 30 or higher and reapply as directed.
- Do not use indoor tanning beds.
- Check your skin regularly for new or changing spots and arrange professional evaluation for concerning changes.
Outlook and Prognosis
Outlook and Prognosis
Many localized skin cancers are highly treatable, particularly when found early. The outlook is less favorable when disease is deeply invasive, involves lymph nodes, or has spread to distant organs. Prognosis differs substantially among basal cell carcinoma, squamous cell carcinoma, and melanoma.
Factors that influence outlook
Clinicians consider the cancer type, stage, tumor thickness or depth, location, recurrence risk, overall health, and response to treatment. A person’s pathology and staging results provide the most useful information for individualized prognostic guidance.
Survivorship & Follow-up
Survivorship and Follow-Up After Skin Cancer
Follow-up after skin cancer varies by cancer type, stage, recurrence risk, and treatment. It may include scheduled skin examinations, lymph-node checks, imaging or laboratory tests when indicated, and review of treatment effects. Your clinician can tailor a skin cancer screening and surveillance plan to your history.
- Keep dermatology and oncology appointments even when the treated area looks healed.
- Perform regular self-exams and report new or changing spots promptly.
- Protect the skin from ultraviolet exposure and avoid indoor tanning.
- Ask about genetic counseling or family-risk assessment when the history suggests it.
- Keep records of pathology, procedures, medicines, and treatment side effects.
When Should You See a Doctor
When Should You See a Doctor?
- A spot is new, changing, asymmetrical, irregularly bordered, multicolored, or unlike your other spots.
- A sore, scab, or growth does not heal within several weeks or repeatedly bleeds or crusts.
- A lesion becomes persistently itchy, painful, tender, or rapidly enlarges.
- You have a personal history of skin cancer or a high-risk immune or family history.
SEEK URGENT HELP
Know when symptoms are urgent
Seek urgent medical care for uncontrolled bleeding, rapidly spreading redness with fever, severe pain after a procedure, or sudden neurologic or breathing symptoms in someone with known advanced disease.
Branches
3 topics
Skin Cancer
Dermatology
Skin Cancer
Medical Oncology
Skin Cancer
Radiation Oncology
