Skin cancer is the most common cancer in fair-skinned populations. Ultraviolet (UV) radiation from the sun and tanning beds damages DNA in skin cells; cumulative and intermittent intense exposure (especially blistering sunburns in youth) drive most cases.
| Type | Origin | Behavior | Typical appearance |
|---|
| Basal cell carcinoma (BCC) — most common | Basal cells of the epidermis | Grows slowly, rarely metastasizes, but can invade and destroy local tissue | Pearly, translucent, dome-shaped papule with rolled borders and fine surface vessels (telangiectasia); may ulcerate centrally ("rodent ulcer"); superficial BCC is a pink scaly patch |
| Squamous cell carcinoma (SCC) | Keratinocytes | Can metastasize, especially on lips, ears, in scars, and in immunosuppressed clients | Firm, scaly, crusted or keratotic nodule that may bleed or ulcerate; can arise in chronic wounds and old scars |
| Melanoma | Melanocytes | Most dangerous — high metastatic potential | Changing pigmented lesion; can arise in an existing mole or new skin |
Precursor: actinic keratosis — rough, scaly patches on sun-exposed skin; a small proportion become SCC.
Melanoma subtypes: superficial spreading (most common in fair skin), nodular (rapid vertical growth), lentigo maligna (sun-damaged face of older adults), and acral lentiginous (palms, soles, under nails — the most common type in people with darker skin; not linked to sun exposure).
Risk factors
- Chronic or intense UV exposure, outdoor work (farming, fishing, construction), tanning beds, history of sunburns
- Fair skin, light hair and eyes, freckling, burns easily
- Many moles or atypical moles, personal or family history of melanoma
- Immunosuppression (organ transplant — SCC risk greatly increased)
- Older age, radiation, arsenic, chronic scars or wounds (SCC), HPV (some SCC)
ABCDE rule for melanoma
| Letter | Warning sign |
|---|
| A — Asymmetry | One half does not match the other |
| B — Border | Irregular, ragged, notched, or blurred edges |
| C — Color | Multiple shades (brown, black, red, white, blue) |
| D — Diameter | Larger than 6 mm (pencil eraser), although melanomas can be smaller |
| E — Evolving | Any change in size, shape, color, elevation, or new symptoms (itching, bleeding, crusting) — the most important sign |
Also use the "ugly duckling" sign: a mole that looks different from the client's other moles.
Full skin assessment: include scalp, ears, between toes, soles, nails, genitals, and the back (use a mirror or partner). Palpate lymph nodes near suspicious lesions.
| Test | Purpose |
|---|
| Skin biopsy — the only way to confirm diagnosis | Shave or punch biopsy for suspected BCC/SCC; excisional biopsy with narrow margins preferred for suspected melanoma so full depth can be measured |
| Dermoscopy | Magnified examination to decide which lesions need biopsy |
| Breslow thickness (depth in mm) and ulceration | Most important prognostic factors for primary melanoma; the core of AJCC T staging |
| Sentinel lymph node biopsy | Staging for melanoma above a thickness threshold or with high-risk features |
| Imaging (CT, PET, MRI brain), LDH | Advanced melanoma staging |
| BRAF mutation testing | Guides targeted therapy in advanced melanoma |
BCC and SCC
- Surgical excision with clear margins — standard for most
- Mohs micrographic surgery — layer-by-layer removal with immediate margin checking; preferred on the face, ears, and for recurrent or high-risk tumors (tissue-sparing, highest cure rate)
- Curettage and electrodesiccation, cryotherapy — small, low-risk lesions on the trunk and limbs
- Topical imiquimod or 5-fluorouracil (5-FU) — superficial BCC in low-risk sites and actinic keratoses
- Radiation — when surgery is not suitable
- Advanced disease: hedgehog pathway inhibitors (vismodegib, sonidegib) for BCC; cemiplimab (immunotherapy) for advanced SCC
Melanoma
- Wide local excision with margins based on Breslow thickness; sentinel node biopsy as indicated
- Advanced or high-risk resected disease: immune checkpoint inhibitors (pembrolizumab, nivolumab, ipilimumab, relatlimab combination); BRAF/MEK inhibitors (dabrafenib + trametinib, encorafenib + binimetinib) for BRAF-mutated tumors
- Radiation for brain or bone metastases
Drug safety
| Drug | Key safety points |
|---|
| Topical 5-FU | Expected redness, crusting, erosion in treated area (a sign it is working); avoid in pregnancy; wash hands; severe toxicity with DPD deficiency; photosensitivity |
| Imiquimod | Local inflammation, flu-like symptoms; avoid sun on treated skin; wash off after the prescribed time |
| Immune checkpoint inhibitors | Immune-related adverse events in any organ: colitis (diarrhea), hepatitis, pneumonitis (cough, dyspnea), endocrinopathies (thyroid, adrenal, pituitary, type 1 diabetes), rash — report early; treated with corticosteroids |
| BRAF/MEK inhibitors | Fever (dabrafenib), photosensitivity, new skin lesions including SCC, reduced ejection fraction, eye problems (retinal changes); regular skin and eye checks |
| Hedgehog inhibitors | Teratogenic — strict contraception; men must use condoms (drug is present in semen); no blood donation during and for months after; muscle spasms, loss of taste, hair loss |
Listed in priority order.
- Postoperative wound care (after wide excision or Mohs)
- Check the dressing and site for bleeding — the first priority right after surgery; apply pressure for oozing and report persistent bleeding
- Monitor for infection, graft or flap viability (color, capillary refill), and pain
- Elevate the site when possible to reduce swelling
- Monitoring during systemic therapy — ask at every visit about diarrhea, cough, dyspnea, fatigue, rash, headache; check thyroid, liver, and glucose results
- Early detection — perform and document skin inspection during routine care; refer any lesion meeting ABCDE or ugly-duckling criteria
- Emotional support — fear of recurrence, disfigurement (face surgery), and uncertainty; refer to support services
- Prevention and education (see below), including community programs targeting high-risk groups such as outdoor workers
Sun protection
- Seek shade, especially from 10 a.m. to 4 p.m.
- Wear wide-brimmed hats, UV-blocking sunglasses, and protective clothing
- Use broad-spectrum sunscreen SPF 30 or higher, apply 15–30 minutes before going out, and reapply every 2 hours and after swimming or sweating
- Avoid tanning beds and sunburns
- Infants under 6 months: keep out of direct sun and use clothing and shade rather than sunscreen
- UV exposure also occurs on cloudy days and is reflected by water, sand, and snow
Skin self-examination
- Monthly, in a well-lit room with full-length and hand mirrors; include scalp, soles, between toes, and nails
- Report new, changing, itching, or bleeding lesions and any sore that does not heal in about a month
After surgery
- Keep the wound clean and dry for the time advised, then showering is usually allowed; cover the site; avoid soaking (baths, pools) until healed as instructed
- Report redness, warmth, pus, fever, or bleeding
- Protect the scar from sun
After a skin cancer diagnosis
- Regular follow-up skin exams — the risk of a second skin cancer is high
- Transplant recipients and others on immunosuppressants need frequent skin checks
| Complication | What to watch for |
|---|
| Postoperative bleeding / hematoma | Soaked dressing, expanding swelling |
| Wound infection, flap or graft failure | Redness, pus, dusky or pale tissue |
| Metastatic melanoma | Enlarged lymph nodes, new neurologic signs (brain), bone pain, cough, weight loss |
| Local tissue destruction | Neglected BCC near eye, nose, or ear |
| Immune-related adverse events | Diarrhea, abdominal pain, dyspnea, jaundice, severe fatigue, hypotension (adrenal crisis) |
| Recurrence | New lesion in or near the scar |
- UV exposure is the main modifiable risk; outdoor workers are a key target for prevention programs
- BCC: most common; pearly papule with rolled edges and telangiectasia; rarely metastasizes
- SCC: scaly, crusted nodule on sun-exposed skin or chronic scar; can metastasize; actinic keratosis is the precursor
- Melanoma is the deadliest; ABCDE plus ugly duckling; E (evolving) is the most important
- Biopsy confirms diagnosis; excisional biopsy preferred for suspected melanoma
- Prognosis: Breslow thickness and ulceration
- Mohs surgery for face and high-risk tumors
- Topical imiquimod or 5-FU for superficial BCC and actinic keratosis — expect local inflammation
- Checkpoint inhibitors: report diarrhea, cough, fatigue early (immune-related events)
- Broad-spectrum SPF 30+, reapply every 2 hours, avoid tanning beds
- Immediate post-op priority: dressing and bleeding check
- Acral lentiginous melanoma (palms, soles, nails) is the most common type in darker skin
Country Notes
United States
- The USPSTF (2023) found insufficient evidence for routine clinician skin examination in asymptomatic adolescents and adults (I statement); a separate 2018 recommendation advises counseling fair-skinned people aged 6 months to 24 years about UV protection (grade B).
- Sunscreens are regulated as over-the-counter drugs by the FDA.
Philippines
- Skin cancer incidence is lower than in fair-skinned populations, and melanoma often presents late on the soles, palms, or nails (acral type); examine these sites routinely.
- Year-round high UV levels and common outdoor occupations (farming, fishing) make sun protection teaching relevant for all ages.