Quick answer. Actinic keratosis is a rough, scaly patch of skin caused by years of sun damage, found on sun-exposed areas like the face, scalp and hands. It is considered pre-cancerous because a small proportion can progress to skin cancer, so any actinic keratosis that grows, bleeds, ulcerates or thickens should be assessed by a doctor.
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Actinic keratosis describes the rough, dry, scaly spots that develop on skin exposed to years of sun, typically on the face, scalp, ears, neck, forearms and backs of the hands. They are very common in older adults and in anyone who has spent a lot of time outdoors, and in sunny Singapore the cumulative ultraviolet exposure that drives them is a year-round reality.
The important thing to understand about actinic keratosis is that it is regarded as pre-cancerous. Most lesions stay harmless, but a small number can slowly progress into a type of skin cancer called squamous cell carcinoma. Because you cannot reliably tell by looking which spots might change, any rough patch that grows, bleeds, ulcerates or thickens deserves a doctor’s attention. This guide explains the signs, the causes and how these spots are treated.
At a glance
| Spot | Typical appearance | What it means |
|---|---|---|
| Actinic keratosis | Rough, scaly, pink or brown patch on sun-exposed skin | Pre-cancerous; small risk of turning into skin cancer |
| Seborrhoeic keratosis | Waxy, 'stuck-on' brown growth | Benign; not related to sun damage or cancer |
| Squamous cell carcinoma | Growing, firm, sometimes ulcerated or bleeding lump | A skin cancer; needs prompt treatment |
| Basal cell carcinoma | Pearly bump, sometimes with visible vessels or a sore that won't heal | The most common skin cancer; treatable when caught early |
| Solar lentigo (age spot) | Flat brown mark, smooth surface | Benign sun-related pigmentation; not scaly |
What is actinic keratosis?
Actinic keratosis, also called solar keratosis, is a patch of rough, scaly skin caused by long-term damage from ultraviolet (UV) radiation, mainly from the sun. The word ‘actinic’ refers to sunlight and ‘keratosis’ to a build-up of the skin’s keratin. Over many years, UV exposure damages skin cells, and these patches are an outward sign of that damage.
They are most common in older adults, in people with fair skin, and in anyone with a lifetime of significant sun exposure, which is relevant in Singapore’s strong, consistent sunshine. Importantly, actinic keratosis is considered a pre-cancerous condition: the cells are abnormal, and a small proportion of lesions can develop into squamous cell skin cancer over time. This is why they are taken seriously even though most remain harmless.
Symptoms & signs
Actinic keratoses usually appear on areas that catch the most sun. Typical features include:
- Rough, dry or scaly patches, often easier to feel (like sandpaper) than to see
- A size usually under a centimetre, though they can be larger
- Colours ranging from skin-toned to pink, red or brown
- Locations such as the face, lips, ears, scalp (especially if balding), neck, forearms and backs of the hands
- Sometimes mild itching, burning or tenderness
People often have several at once, reflecting widespread sun damage in the area. A patch that grows quickly, becomes thicker or lumpy, bleeds, crusts, ulcerates or fails to heal is a warning sign and should be checked by a doctor, as it may indicate the spot is turning into skin cancer.
Causes & risk factors
The cause is cumulative UV damage to the skin over many years. Factors that raise the risk include:
- Long-term sun exposure, including outdoor work, sport or recreation, which is significant in a sunny climate like Singapore’s
- Fair skin that burns easily, light hair and light eyes
- Older age, as the damage accumulates over a lifetime
- A history of frequent sunburn or use of tanning beds
- A weakened immune system, for example after an organ transplant or with certain medications
Because the underlying driver is sun damage, sun protection is central both to preventing new lesions and to lowering the long-term risk of skin cancer.
How it's diagnosed
A doctor or dermatologist can usually diagnose actinic keratosis by examining the skin, often using a dermatoscope (a special magnifying light) to look more closely. They will:
- Inspect the patch and feel its rough texture
- Check surrounding sun-exposed skin for other lesions
- Assess for any features suggesting it has progressed, such as thickening, a lump, bleeding or an ulcer
If there is any doubt, or if a lesion looks like it could be turning into skin cancer, the doctor will take a small skin sample (a biopsy) and send it to the laboratory. This confirms the diagnosis and rules out squamous cell carcinoma, which is the main reason these spots are monitored carefully.
Treatment options
Treatment aims to clear the abnormal cells and reduce the risk of progression to skin cancer. The approach depends on how many lesions there are and where they sit. Options include:
- Cryotherapy (freezing with liquid nitrogen), a quick clinic procedure for individual spots
- Topical creams or gels applied over days to weeks to treat areas with several lesions
- Curettage (scraping the lesion), sometimes used for thicker spots
- Photodynamic therapy, a light-based treatment for larger affected areas
Alongside treating existing spots, sun protection is essential: regular broad-spectrum sunscreen, hats, sleeves and avoiding the midday sun help prevent new lesions and lower cancer risk. Because new actinic keratoses can keep forming, ongoing skin checks are sensible. Costs vary by the number of lesions and method used, and a dermatologist can advise on what is appropriate for your skin.
When to see a doctor & which specialist
You should have any persistent rough, scaly patch on sun-exposed skin assessed, and see a doctor promptly if you notice any of these warning signs that a spot may be becoming a skin cancer:
- A patch that grows, thickens or becomes lumpy
- Bleeding, crusting, ulceration or a sore that will not heal
- Tenderness, rapid change, or a spot that looks different from the others
While actinic keratosis itself is not an emergency, do not ignore these changes, as early skin cancer is far easier to treat. A dermatologist is the right specialist to diagnose actinic keratosis, treat it, check for skin cancer with a biopsy if needed, and set up a sun-protection and monitoring plan. If you have multiple sun-damaged spots or a personal history of skin cancer, regular dermatology review is worthwhile.
Related guides
- Best Dermatology Clinics in Singapore — our editorial shortlist
- dermatology clinics directory
- Tinea versicolor
- Perioral dermatitis
- Tonsil stones
- Eustachian tube dysfunction
- Post-nasal drip
Sources
- Mayo Clinic – Actinic keratosis
- NHS – Actinic keratoses (solar keratoses)
- American Academy of Dermatology – Actinic keratosis
- HealthHub Singapore – Skin cancer
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