What is actinic keratosis?
Actinic keratosis (AK) is a rough, dry, scaly patch of skin caused by years of cumulative sun exposure. It's one of the most common reasons Australians see a skin cancer doctor — a reflection of just how much UV damage accumulates over a lifetime in our climate.
AKs are considered pre-cancerous: most never progress further, but a small proportion can develop into squamous cell carcinoma (SCC) over months to years if left untreated. Because it's not possible to predict which individual AK will progress, we generally recommend treating them.
Causes and risk factors
- Cumulative lifetime UV exposure — the single biggest driver.
- Fair skin that burns easily and tans poorly.
- Age — becoming more common from the 40s onward.
- A history of significant sun exposure, particularly outdoor work or recreation.
- Immunosuppression, which increases both the number of AKs and their risk of progression.
Signs to look for
- A rough, dry, sandpaper-like patch — often easier to feel than to see.
- Pink, red, or skin-coloured colouring, sometimes with a scaly or crusted surface.
- Usually a few millimetres to a couple of centimetres across.
- Frequently multiple patches on chronically sun-exposed skin — face, scalp (especially if balding), ears, forearms and the backs of the hands.
⚠ See a doctor if
A patch becomes thickened, tender, raised, or starts to grow — these can be signs of progression toward squamous cell carcinoma and warrant prompt review.
Diagnosis
Most AKs are diagnosed on examination and dermoscopy. If a lesion looks thickened, unusually tender, or otherwise atypical for a straightforward AK, we'll recommend a biopsy to rule out early SCC.
Treatment options
Cryotherapy
Freezing with liquid nitrogen — our most common treatment for individual or a small number of AKs.
Photodynamic therapy (PDT)
A light-activated topical treatment well suited to larger areas of sun-damaged skin with multiple AKs, particularly on the face and scalp.
Topical field treatments
Creams applied over a wider area of sun-damaged skin to treat visible and subclinical AKs together.
Biopsy or excision
For any lesion that looks atypical or isn't responding as expected, to rule out progression to SCC.
Prevention
- Daily SPF 30+ broad-spectrum sunscreen on exposed skin, reapplied every two hours outdoors.
- A broad-brimmed hat and UPF clothing on chronically exposed areas — scalp, ears, forearms.
- Regular skin checks — AKs often signal broader sun damage worth monitoring for BCC and SCC too.
Frequently asked questions
Will every actinic keratosis turn into cancer?
No — most never progress. But because it isn't possible to predict which ones will, and because treatment is quick and low-risk, we generally recommend treating AKs rather than watching and waiting.
Does cryotherapy hurt?
It causes a brief stinging or burning sensation during treatment, followed by some redness and possibly blistering over the following days as the treated skin heals. Most people find it very manageable.
Can actinic keratosis come back after treatment?
Yes — because AK reflects broader cumulative sun damage, new patches can appear over time, especially without good sun protection. Regular skin checks help catch and treat new ones early.