What is an actinic keratosis?
An actinic keratosis is a scaly spot found on sun-damaged skin. It is also known as solar keratosis. It is considered precancerous or an early form of cutaneous squamous cell carcinoma.
What are the clinical features of actinic keratosis?
Actinic keratosis may be solitary but there are often multiple keratoses. The appearance varies.
- A flat or thickened papule or plaque
- White or yellow; scaly, warty or horny surface
- Skin coloured, red or pigmented
- Tender or asymptomatic
Actinic keratoses are very common on sites repeatedly exposed to the sun, especially the backs of the hands and the face, most often affecting the ears, nose, cheeks, upper lip, vermilion of the lower lip, temples, forehead and balding scalp. In severely chronically sun damaged individuals, they may also be found on the upper trunk, upper and lower limbs, and dorsum of feet.
Complications of actinic keratoses
The main concern is that actinic keratoses predispose to squamous cell carcinoma. It is rare for a solitary actinic keratosis to evolve to squamous cell carcinoma (SCC), but the risk of SCC occurring at some stage in a patient with more than 10 actinic keratoses is thought to be about 10 to 15%. A tender, thickened, ulcerated or enlarging actinic keratosis is suspicious of SCC.
What is the treatment for actinic keratoses?
Actinic keratoses are usually removed because they are unsightly or uncomfortable, or because of the risk that skin cancer may develop in them. Physical treatments are used to destroy individual keratoses that are generally symptomatic or have a thick hard surface scale. The lesions may recur in time, in which case they may be retreated by the same or a different method.
Liquid nitrogen spray is required to ensure adequate depth and duration of freeze. This varies according to lesion location, width and thickness. Healing varies from 5–10 days on face, 3–4 weeks on the hands, and 6 weeks or longer on the legs. A light freeze for a superficial actinic keratosis usually leaves no mark, but longer freeze times result in hypopigmentation or scar.
Shave, curettage (scraping with a sharp instrument) and electrocautery (burning) may be necessary to remove a cutaneoushorn or hypertrophic actinic keratosis. Healing of the wound takes several weeks or longer, depending on body site. A specimen is sent for pathological examination.
Excision ensures the actinic keratosis has been completely removed, which should be confirmed by pathology. The surgical wound is sutured (stitched). The sutures are removed after a few days, the time depending on the size and location of the lesion. The procedure leaves a permanent scar.
On DermNet NZ:
- Skin cancer
- Bowen disease (squamous cell carcinoma in situ)
- Squamous cell carcinoma
- Basal cell carcinoma