Actinic keratosis: the rough, scaly sun spot you shouldn't ignore
An actinic keratosis (AK), also called a solar keratosis, is a rough, scaly patch that forms on skin damaged by years of sun exposure. It's one of the clearest signs that UV has damaged your skin's DNA, and it's considered a precancerous lesion.
- AKs are caused by DNA damage from UVB and appear on sun-exposed skin: face, ears, scalp, backs of hands.
- A single AK rarely turns into cancer, but people with many AKs have a higher risk of squamous cell carcinoma.
- A tender, thick, bleeding or growing spot should be checked promptly.
What it is
According to DermNet: Actinic keratosis, an actinic keratosis is a precancerous scaly spot on sun-damaged skin that may be considered an early form of cutaneous squamous cell carcinoma (SCC). AKs result from abnormal skin cell development due to DNA damage from short-wavelength UVB, and they're more likely when immune function is weakened by age, illness or certain medicines.
What it looks like
- A flat or thickened bump or patch, often feeling gritty or sandpaper-rough, sometimes easier to feel than to see.
- A white or yellow scaly, warty or horny surface; skin-colored, red or pigmented.
- Often several at once, on the backs of the hands, ears, nose, cheeks, lips, temples, forehead and balding scalp.
Who gets them
DermNet lists fair skin with a history of sunburn, long hours outdoors for work or recreation, other signs of sun-aged skin, and a weakened immune system as predisposing factors. AKs are common even in cloudy climates: DermNet notes that in southern Ireland and northwest England, up to 25% of people aged 60 and over have at least one. People who used tanning beds or tan intentionally build up the same UV damage (see tanning beds and UV risk).
Why it matters
DermNet says it's rare for a single AK to become SCC, but the risk of SCC at some point in someone with more than 10 AKs is thought to be about 10 to 15%. People with AKs are also at higher risk of other skin cancers, including basal cell carcinoma and melanoma (see types of skin cancer).
Warning signs: a keratosis that is tender, thickened, ulcerated or enlarging is suspicious for SCC and should be seen by a doctor promptly.
Treatment and prevention
Doctors usually diagnose AKs by looking at them, sometimes with a dermatoscope or biopsy. Options include freezing with liquid nitrogen (cryotherapy), prescription creams such as fluorouracil or imiquimod for wider areas, and photodynamic therapy (PDT). DermNet notes that some AKs resolve with frequent, appropriate sunscreen use, and that flat, symptom-free keratoses may just be monitored.
Prevention is the same as for skin cancer: daily broad-spectrum sunscreen (see SPF explained), protective clothing, shade at midday (check the UV index), and regular skin checks.
Educational information only, not medical advice. See a board-certified dermatologist for diagnosis and treatment. See our medical disclaimer.
Published October 28, 2026. Sources are linked in the text. See our Medical Disclaimer.