Most of us grew up thinking of sun damage as wrinkles, freckles, and the odd sunspot — cosmetic concerns rather than medical ones. But some of that damage is more than skin deep. Actinic keratoses (AKs) are one of the most common things I diagnose in clinic, and while a single lesion is rarely dangerous on its own, they're a genuine early warning sign: a marker that skin cells have accumulated enough UV damage to start behaving abnormally, with a real — if generally low — chance of progressing to skin cancer. Here's what actinic keratosis actually is, why it matters, and how we approach treatment.
An actinic keratosis (also called a solar keratosis) is a rough, scaly patch of skin that develops where skin cells have been damaged by cumulative ultraviolet (UV) exposure over years or decades. They're considered a precancerous lesion — an early, in-situ stage of skin cell change that sits on the same biological pathway as cutaneous squamous cell carcinoma (SCC), one of the more common forms of skin cancer.
AKs typically appear as pink, red, brown, or skin-coloured patches with a dry, sandpaper-like or crusty surface. They're often easier to feel than to see, particularly in their early stages. The most common sites are the areas that get the most lifetime sun exposure — the face, ears, scalp (especially in those with thinning hair), lips, forearms, and the backs of the hands.
AKs form when UVB radiation damages the DNA of keratinocytes, the main cells of the outer skin layer, faster than the skin can repair itself. Over time, this damage accumulates and produces visibly and structurally abnormal skin cells.
Given our climate and UV index, this is an extremely common presentation in Australian dermatology clinics. Risk is higher in people with:
It's also common to see AKs cluster in areas of more diffuse, longstanding sun damage — a phenomenon we call field cancerisation, where the surrounding skin, not just the visible lesion, carries UV-related genetic changes. This is an important concept, because it's part of why we often treat the broader area of damaged skin, not only the spot you can see.
Not yet — but they're on the pathway. The risk of any single untreated AK progressing to a squamous cell carcinoma is generally low (estimates for an individual lesion range from under 1% up to around 10% over time), and some lesions can even resolve on their own. However, that risk compounds: people with numerous AKs — particularly more than ten — face a meaningfully higher cumulative likelihood of developing an SCC somewhere in that field of damaged skin over time.
This is why we treat AKs seriously, even when an individual patch looks unremarkable. It's also why any lesion that becomes tender, thickened, rapidly growing, bleeding, or ulcerated needs prompt review — these are features that raise concern for progression to invasive skin cancer and shouldn't be watched and waited on.
Diagnosis usually starts with a full skin examination — both looking and feeling, since AKs are often more palpable than visible. In my clinic, this includes:
A comprehensive skin check is also an opportunity to assess your broader sun-damage burden and skin cancer risk, not just the lesion that prompted the visit.
Treatment choice depends on the number, thickness, and distribution of lesions, and on your skin type and preferences. At Skindepth, our approach for actinic keratosis and broader field damage centres on:
Topical field therapy, which treats the wider area of sun-damaged skin rather than just individual visible spots — directly addressing the field cancerisation process described above. Options include prescription creams and gels such as 5-fluorouracil, imiquimod, and diclofenac gel, applied over a defined course (typically several weeks, depending on the agent). These work by targeting abnormal cells across the treated area; it's normal to see redness, scaling, or crusting during treatment as damaged skin cells are cleared — this is an expected part of the process, not a complication, though we'll talk you through exactly what to expect.
Photodynamic therapy (PDT) is a light-activated treatment particularly well suited to broader areas of field damage or facial/scalp involvement. A photosensitising solution is applied to the skin, allowed to absorb into the abnormal cells, and then activated with a specific wavelength of light, which selectively targets the affected tissue. PDT can be delivered over one or more sessions depending on the extent of damage, and is a well-established option in the dermatology literature for field-directed treatment of actinic keratosis.
The right treatment — or combination — is something we determine after examining your skin, since the ideal approach for a few scattered lesions differs from that for widespread field damage.
Because AKs reflect cumulative UV damage, prevention is central to managing them long-term:
Treating existing lesions without addressing ongoing UV exposure means new AKs are likely to keep appearing.
Any new, persistent, scaly, or rough patch of skin — especially on a sun-exposed area — is worth having examined, as is any existing AK that changes: becoming thicker, tender, larger, or prone to bleeding. Given the link to skin cancer risk, this isn't a "wait and see" category of skin change.
Can actinic keratosis go away on its own?Some individual lesions do regress without treatment, but many persist or grow, and it's not possible to predict which will behave which way — so treatment or monitoring by a dermatologist is generally recommended rather than waiting.
Is actinic keratosis the same as skin cancer?No — it's a precancerous change. It sits on the pathway to squamous cell carcinoma but isn't invasive cancer itself. Progression happens in a minority of lesions, but the risk is real enough to warrant treatment and follow-up.
Does having actinic keratosis mean I'll get skin cancer?Not necessarily, but it does indicate significant cumulative sun damage and raises your overall risk of skin cancer, which is why ongoing sun protection and regular skin checks matter.
How long does treatment take to work?This depends on the therapy. Topical field treatments are typically applied over several weeks, with visible skin reactions during that period; photodynamic therapy works over one or more sessions. We'll set expectations for your specific treatment plan at your consultation.
If you've noticed a rough or persistent patch of skin, or it's simply been a while since your last skin check, we'd encourage you not to leave it. At Skindepth Dermatology in Melbourne and Perth, we offer thorough skin examinations and evidence-based treatment for actinic keratosis, including topical field therapy and photodynamic therapy, tailored to your skin and the extent of sun damage. [Book a consultation] with our team to get started.
This article is general information only and does not replace individualised medical advice. Any new or changing skin lesion should be assessed by a qualified dermatologist, and treatment should only be commenced following an individual consultation.
Dr Alice Rudd FACD is a Specialist Dermatologist and Fellow of the Australasian College of Dermatologists, and founder of Skindepth Dermatology.