In short. Actinic keratosis, Bowen disease, basal cell carcinoma and squamous cell carcinoma: what they look like, why early removal is straightforward, and what delay costs.
Key points
- Examine the whole skin surface periodically, including the scalp, behind the ears, the nails and the soles.
- The features worth acting on are a lesion that is new, changing, asymmetric, irregular in border or colour, larger than about six millimetres, or simply not healing after several weeks.
- Photographs taken at intervals help, because change over time is often easier to see than any single appearance.
Skin cancer is among the commonest cancers in people with pale skin, and one of the few that can often be seen before it becomes dangerous. The lesions that matter fall into two groups: the pre-cancerous changes that may progress if left alone, and the cancers themselves.
Pre-cancerous lesions
Actinic keratosis appears as a rough, scaly, sometimes tender patch on sun-exposed skin — face, scalp, ears, forearms and the backs of the hands. It is a marker of cumulative sun damage rather than a cancer, and a small proportion do progress. Bowen disease is a squamous cell carcinoma in situ: a persistent, slowly enlarging red scaly patch that has not yet become invasive. Both are treatable, and treating them is far simpler than treating an invasive tumour.
The two common skin cancers
Basal cell carcinoma is the commonest and the least dangerous. It typically appears as a pearly or translucent nodule, sometimes with visible small blood vessels, or as a sore that bleeds, crusts and never quite heals. It grows locally and only very rarely spreads, but it destroys tissue as it enlarges, and a lesion on the eyelid or nose is much easier to treat when it is small.
Squamous cell carcinoma is more likely to spread. It usually presents as a firm, scaly or crusted lump, or as a non-healing ulcer, and it behaves more aggressively in immunosuppressed patients and on the lips and ears.
What to look at, and how
Examine the whole skin surface periodically, including the scalp, behind the ears, the nails and the soles. The features worth acting on are a lesion that is new, changing, asymmetric, irregular in border or colour, larger than about six millimetres, or simply not healing after several weeks. Photographs taken at intervals help, because change over time is often easier to see than any single appearance.
Why early recognition matters
When these tumours are removed early, treatment is usually a minor procedure and the outcome is excellent. Delay changes that: the excision becomes larger, the reconstruction more involved, and for squamous cell carcinoma the risk of spread rises. Dermoscopy and, where needed, a biopsy are what turn a suspicion into a diagnosis.
Arrange assessment promptly if
- A spot or sore is new, changing in size, shape or colour, or bleeding, crusting or itching without explanation.
- A lesion has failed to heal after several weeks, or heals and then breaks down repeatedly.
- You have had a previous skin cancer, or you are immunosuppressed, and notice any new or changing lesion.
Frequently asked questions
What is the difference between actinic keratosis and skin cancer?
Actinic keratosis is a rough, scaly, sometimes tender patch that marks cumulative sun damage rather than being a cancer, though a small proportion do progress. Bowen disease is a squamous cell carcinoma in situ: a persistent, slowly enlarging red scaly patch that has not yet become invasive.
How does basal cell carcinoma differ from squamous cell carcinoma?
Basal cell carcinoma is the commonest and least dangerous: a pearly or translucent nodule, or a sore that bleeds, crusts and never quite heals. It destroys tissue as it enlarges but only very rarely spreads. Squamous cell carcinoma is more likely to spread and behaves more aggressively on the lips and ears.
Why does early removal of these lesions matter so much?
When they are removed early, treatment is usually a minor procedure and the outcome is excellent. Delay makes the excision larger and the reconstruction more involved, and for squamous cell carcinoma the risk of spread rises. A lesion on the eyelid or nose is much easier to treat when small.
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.