In short. What cumulative sun damage leaves behind, how the three main skin cancers present, who benefits from a full skin check, and how to examine your own skin properly.
Key points
- Once a month, in good light, look at your whole skin including the scalp, back, and between the toes, using a mirror and someone else’s eyes for what you cannot see.
- What matters is change in one specific lesion, not perfection.
- Photograph anything you are unsure of, with a ruler for scale, and compare it at the next check.
Skin cancer is the commonest cancer in fair-skinned populations, and one of the most treatable when it is found early. The great majority of cases are caused by cumulative ultraviolet exposure — sunburn, tanning, and the light that reaches skin over a lifetime. That makes it unusually preventable, and unusually suitable for screening.
Actinic damage: what the sun leaves behind
Ultraviolet light damages skin in ways that accumulate quietly: freckling, solar lentigines, mottled pigmentation, broken vessels, a leathery texture, and actinic keratoses — rough, scaly patches on sun-exposed sites that are not cancer but are markers of damage and can, in a minority of cases, progress. Treatment can clear the visible lesions, but it cannot undo the damage that produced them, which is why prevention is the more valuable intervention.
The three main skin cancers
Basal cell carcinoma is the commonest, grows slowly, rarely spreads, and usually appears as a pearly or translucent bump, a non-healing sore, or a scar-like patch. Squamous cell carcinoma is more likely to spread if neglected and often presents as a firm, scaly, tender lump or a sore that will not heal. Melanoma is the most dangerous; it may arise in a pre-existing mole or on normal skin, and it is recognised by change — in size, shape, colour, or behaviour.
What screening involves
A skin check is a structured examination of the whole skin surface, with dermoscopy used on anything suspicious. Photographic monitoring of many moles can help track change over time. Screening is most useful for people at higher risk: fair skin that burns easily, a history of sunburn or tanning-bed use, many or unusual moles, a previous skin cancer, a family history of melanoma, immunosuppressive treatment, or substantial occupational sun exposure.
Screening has a cost as well as a benefit: examinations find many harmless lesions, and removing all of them would mean unnecessary procedures and scars. The value of a skin check lies in finding the lesions that genuinely need treating, which is why dermoscopy and, where indicated, biopsy decide the question rather than appearance alone.
Checking yourself, honestly
Once a month, in good light, look at your whole skin including the scalp, back, and between the toes, using a mirror and someone else’s eyes for what you cannot see. What matters is change in one specific lesion, not perfection. Photograph anything you are unsure of, with a ruler for scale, and compare it at the next check.
See a dermatologist promptly if a lesion
- Is changing in size, shape, or colour, or looks different from your other moles.
- Bleeds, itches, crusts, or fails to heal over several weeks without explanation.
- Appears as a new, firm, growing lump, or a sore that repeatedly scabs and returns.
Frequently asked questions
What does cumulative sun damage leave behind?
Freckling, solar lentigines, mottled pigmentation, broken vessels, a leathery texture and actinic keratoses: rough scaly patches that are markers of damage and can, in a minority of cases, progress. Treatment clears the visible lesions but cannot undo the damage that produced them.
How do the three main skin cancers differ?
Basal cell carcinoma is the commonest, grows slowly and rarely spreads. Squamous cell carcinoma is more likely to spread if neglected. Melanoma is the most dangerous and is recognised by change in size, shape, colour or behaviour, whether it arises in a mole or on normal skin.
Who benefits most from a full skin check?
Fair skin that burns easily, a history of sunburn or tanning-bed use, many or unusual moles, a previous skin cancer, a family history of melanoma, immunosuppressive treatment, or substantial occupational sun exposure. In darker skin tones melanoma more often appears on palms, soles and nails.
Risks & Limitations
- Most chronic skin disease is managed rather than cured, and relapse is expected.
- Treatments typically need 8–12 weeks before response can be judged fairly.
- Topical treatment can cause irritation, dryness, peeling and photosensitivity.
- Systemic therapy may require blood monitoring and carries organ, metabolic and pregnancy risks.
- Isotretinoin in particular requires strict monitoring and pregnancy prevention.
- Pigment change is often slow and may be incomplete.
- No treatment works for everyone, and response cannot be predicted with certainty.
When to Seek Care
- A mole or lesion that changes in size, shape or colour, or starts to bleed, itch or crust.
- Fever with a widespread rash, blistering, or rash involving the eyes, mouth or genitals — seek emergency care.
- Rapidly spreading redness, swelling or pain in the skin.
- Facial swelling or difficulty breathing — possible severe reaction; seek emergency care immediately.
- New or worsening symptoms while taking a monitored medication.
References & Further Reading
- American Academy of Dermatology (AAD) — public and clinical guidance
- World Health Organization (WHO) — skin and infectious disease resources
- Chinese Medical Association, Dermatology Branch — clinical guidance
- Cochrane Library — systematic reviews in dermatology
This page is patient education, not medical advice, and it does not cite individual studies. Discuss your own case with a qualified clinician. To arrange an assessment at Chongqing West District Hospital, see Contact & Consultation.