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Melanoma - Causes, Treatment & When to See a Doctor

📅 Updated: April 2026 ⏱ 6 min read ✅ Medically reviewed

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Melanoma – Causes, Symptoms, Diagnosis & Treatment

Melanoma: What You Need to Know

What is Melanoma?

Melanoma is a malignant tumor that originates from melanocytes, the cells that produce the pigment melanin and give skin its color. Although it accounts for only about 1% of skin cancers, melanoma is responsible for the majority of skin‑cancer deaths because it can spread (metastasize) rapidly to other organs if not caught early. Most melanomas develop on skin that has been exposed to ultraviolet (UV) radiation, but they can also appear on mucous membranes (mouth, vagina, anus), the eyes (uveal melanoma), and even inside the body (rare).1

Common Causes

Melanoma is not caused by a single factor; rather, a combination of genetic, environmental, and lifestyle factors increases risk. The following are the most frequently identified contributors:

  • Ultraviolet (UV) radiation – Cumulative exposure to sunlight and artificial sources such as tanning beds damages DNA in melanocytes.
  • Fair skin, red or blond hair, and blue/green eyes – Less melanin provides less natural protection against UV rays.
  • History of sunburns, especially blistering burns in childhood.
  • Multiple atypical (dysplastic) nevi – Having many unusual moles raises the chance of malignant transformation.
  • Family history of melanoma – Mutations in genes such as CDKN2A and BRAF run in families.
  • Personal history of melanoma or other skin cancers.
  • Weakened immune system – Organ‑transplant recipients, HIV infection, or immunosuppressive medications increase risk.
  • Exposure to certain chemicals – Arsenic and some pesticides have been linked to skin cancer.
  • Hormonal influences – Some studies suggest that estrogen may modestly affect melanoma risk, especially in women who use hormone‑replacement therapy.
  • Rare genetic syndromes – Familial atypical multiple mole melanoma (FAMMM) syndrome, xeroderma pigmentosum, and BAP1‑tumor predisposition syndrome.

Associated Symptoms

Melanoma may appear as a new spot or a change in an existing mole. The classic “ABCDE” criteria help identify suspicious lesions:

  • Asymmetry – One half does not match the other.
  • Border irregularity – Edges are ragged, notched, or blurred.
  • Color variation – Shades of brown, black, tan, red, blue, or white within the same lesion.
  • Diameter – Typically >6 mm (about the size of a pencil eraser), though some melanomas are smaller.
  • Evolving – Any change in size, shape, color, elevation, or symptoms such as itching or bleeding.

Other symptoms that may accompany a melanoma include:

  • Itching, tenderness, or pain at the lesion
  • Bleeding or oozing from the spot
  • Surface crust or ulceration
  • Swelling of nearby lymph nodes (possible sign of metastasis)
  • Unexplained weight loss, fatigue, or night sweats in advanced disease

When to See a Doctor

Because early detection dramatically improves outcomes, schedule an appointment promptly if you notice any of the following:

  • A new mole after age 20 that looks different from your other moles.
  • Any existing mole that changes in size, shape, color, or texture.
  • A mole that itches, hurts, bleeds, or becomes a sore that won’t heal.
  • Growth of a mole that is larger than a pencil eraser.
  • Multiple moles that look irregular or have “ugly duckling” characteristics (significantly unlike your other moles).

If you belong to a high‑risk group (family history, many atypical nevi, immunosuppression), consider a full‑body skin exam by a dermatologist at least once a year.

Diagnosis

Healthcare providers use a stepwise approach:

1. Visual examination

A dermatologist will perform a thorough skin inspection, often with a dermatoscope – a magnifying device that reveals structures invisible to the naked eye.

2. Biopsy

Any lesion suspected of melanoma is biopsied. Common techniques include:

  • Excisional biopsy – Entire lesion removed with a narrow margin of normal skin (preferred for most melanomas).
  • Punch biopsy – Small circular piece taken when excision would cause excessive scarring.
  • Incisional biopsy – Only part of a large lesion is removed for diagnosis.

The tissue is examined under a microscope to determine the type (e.g., superficial spreading, nodular, lentigo maligna) and depth of invasion (Breslow thickness), which are critical for staging.

3. Staging work‑up

If the melanoma is >0.8 mm thick or shows high‑risk features, further tests assess spread:

  • Sentinel lymph‑node biopsy (SLNB) – a radioactive tracer identifies the first draining lymph node; the node is removed and examined.
  • Imaging studies – CT, PET/CT, MRI, or ultrasound based on tumor stage and symptoms.
  • Blood tests – LDH level can be a prognostic marker in advanced disease.

Treatment Options

Treatment is tailored to the stage, location, and patient health. The primary goal is complete removal of cancerous cells while preserving function and appearance.

Surgical interventions

  • Wide local excision – Removal of the melanoma with a margin of normal skin (usually 1–2 cm for thin lesions, up to 3 cm for thicker tumors).
  • Mohs micrographic surgery – Layer‑by‑layer removal used for melanomas in cosmetically sensitive areas (e.g., face).
  • Sentinel lymph‑node biopsy – Provides staging information; if positive, a complete lymph‑node dissection may be recommended.

Adjuvant (post‑surgery) therapies

  • Immunotherapy – Checkpoint inhibitors such as pembrolizumab (Keytruda) and nivolumab (Opdivo) stimulate the immune system to attack residual cancer cells.
  • Targeted therapy – For tumors with BRAF V600E/K mutations, drugs like vemurafenib, dabrafenib, and trametinib block the mutated signaling pathway.
  • Radiation therapy – Used when surgical margins are positive, for certain nodal basins, or for brain metastases.
  • Interferon‑alpha – Less common today but still an option in specific scenarios.

Systemic treatments for advanced disease

  • Combination immunotherapy (nivolumab + ipilimumab) – improves survival in metastatic melanoma.
  • Approved targeted‑therapy combos for BRAF‑mutant melanoma (dabrafenib + trametinib).
  • Clinical trials – Ongoing research into novel agents (e.g., oncolytic viruses, tumor‑infiltrating lymphocytes).

Home & supportive care

While melanoma treatment is medical, supportive measures help patients cope:

  • Sun‑protected skin care – Broad‑spectrum sunscreen (SPF 30+), protective clothing, and hats.
  • Wound care – Keep surgical sites clean, follow surgeon’s instructions for dressings.
  • Psychological support – Counseling, support groups, or a mental‑health professional.
  • Nutrition and exercise – Balanced diet and regular activity support immune health during treatment.

Prevention Tips

Most melanomas are preventable with diligent sun protection and skin surveillance:

  • Apply sunscreen generously (SPF 30 or higher) 15 minutes before outdoor exposure and reapply every 2 hours, or after swimming/sweating.
  • Seek shade between 10 a.m. and 4 p.m. when UV intensity peaks.
  • Wear protective clothing – Long‑sleeved shirts, wide‑brim hats, and UV‑blocking sunglasses.
  • Avoid indoor tanning – Tanning beds emit intense UV radiation and increase melanoma risk.
  • Perform regular skin checks – Use a mirror or enlist a partner to examine hard‑to‑see areas (back, scalp).
  • Know your mole profile – Take photos of atypical moles and note changes over time.
  • Schedule annual dermatologist exams – Particularly important for high‑risk individuals.
  • Maintain a healthy immune system – Adequate sleep, balanced diet, and avoiding tobacco.

Emergency Warning Signs

Rapidly enlarging or ulcerating skin lesion – May indicate aggressive melanoma.

Sudden onset of severe pain, swelling, or numbness around a known melanoma – Possible infection or metastatic involvement.

New, unexplained lumps in the neck, underarm, groin, or elsewhere – Could be metastatic lymph nodes.

Persistent fever, night sweats, or unexplained weight loss – Signs of advanced disease.

If you experience any of these signs, seek urgent medical attention (emergency department or rapid‑access oncology service).

Key Take‑aways

Melanoma is a serious but often preventable form of skin cancer. Early detection through self‑examination and professional skin checks, combined with diligent sun protection, offers the best chance for cure. When diagnosed, a range of effective surgical, systemic, and supportive therapies can achieve long‑term remission, especially when treatment begins at an early stage.

References

  1. Mayo Clinic. “Melanoma.” Accessed March 2024. https://www.mayoclinic.org/diseases-conditions/melanoma/symptoms-causes/syc-20374884
  2. American Cancer Society. “Skin Cancer Facts & Figures 2024.” https://www.cancer.org/cancer/melanoma-skin-cancer/about/what-is-melanoma.html
  3. National Cancer Institute. “Melanoma Treatment (PDQ¼)–Patient Version.” Updated 2023. https://www.cancer.gov/types/skin/patient/melanoma-treatment-pdq
  4. Cleveland Clinic. “Melanoma Diagnosis and Staging.” 2023. https://my.clevelandclinic.org/health/diseases/16208-melanoma
  5. World Health Organization. “Ultraviolet Radiation and the Skin.” 2022. https://www.who.int/uv/health/en/

⚠ Medical Disclaimer

Important: The information provided on this page is for general informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.

If you think you may have a medical emergency, call your doctor, go to the emergency department, or call 911 immediately.

📚 Medical References