Actinic keratosis

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Alternative names

Solar keratosis; Sun-induced skin changes - keratosis; Keratosis - actinic (solar)
Definition

Actinic keratosis is a precancerous skin growth usually caused by sun exposure.

Causes, incidence, and risk factors

Actinic keratosis occurs most commonly in fair skin, especially in the elderly and in young individuals with light complexions. The growths occur in sun-exposed skin areas. The growths begin as flat, scaly areas that later develop a hard wart-like surface.

They are classified as precancerous growths. If left untreated, approximately 1% of actinic keratoses develop into squamous cell carcinoma.

Symptoms

Rough and dry textured skin lesion
A macule, patch, or growth on the skin
Limited to a discrete area (localized)
Located on the face, scalp, back of the hands, chest or other sun-exposed areas
Gray, pink, red (erythematous), or the same color as the skin
Initially flat and scaly on the surface, becoming slightly raised
Becoming hard and wart-like or gritty, rough, and "sandpapery" -- may develop a horn-like texture from overgrowth of skin keratin layer (hyperkeratosis)
The skin lesion may be easier to feel than to see.
Signs and tests

The health care provider bases the diagnosis on the appearance of the skin growth. A skin biopsy could reveal signs of cancerous changes, if present.

Treatment

Because actinic keratoses represent precancerous changes, you should have them examined promptly and follow the health care provider's advice for treatment.

Growths may be removed by cryotherapy (freezing), electrical cautery (burning), or surgery. Growths may also be treated with medications that cause skin peeling or removal. More recently, lasers and other light sources have been used to treat actinic keratoses.

Expectations (prognosis)

Actinic keratosis itself is benign, but it may develop into skin cancer. Removal of the growth is usually effective.

Complications

Squamous cell carcinoma
Irritation and discomfort of the skin growth
Calling your health care provider Return to top

Call for an appointment with your health care provider if areas of persistent roughness or scaliness develop in sun-exposed skin.

Prevention

Reduce sun exposure and protect your skin from the sun. Wear protective clothing such as hats, long-sleeved shirts, long skirts, or pants. Ultraviolet light is most intense midday, so try to avoid sun exposure during these hours.

Use high-quality sunscreens, preferably with SPF (sun protection factor) ratings of at least 15. Pick a sunscreen that blocks both UBA and UVB light. Apply sunscreen at least 30 minutes before going out into the sun, and reapply frequently. Sunscreen should be used year-round, including in the winter.

Skin cancer is a disease in which malignant (cancer) cells form in the tissues of the skin.

The skin is the body’s largest organ. It protects against heat, sunlight, injury, and infection. Skin also helps control body temperature and stores water, fat, and vitamin D. The skin has several layers, but the two main layers are the epidermis (upper or outer layer) and the dermis (lower or inner layer). Skin cancer begins in the epidermis, which is made up of 3 kinds of cells:

Squamous cells: Thin, flat cells that form the top layer of the epidermis.
Basal cells: Round cells under the squamous cells.
Melanocytes: Found in the lower part of the epidermis, these cells make melanin, the pigment that gives skin its natural color. When skin is exposed to the sun, melanocytes make more pigment, causing the skin to darken.
Skin cancer can occur anywhere on the body, but it is most common in skin that has been exposed to sunlight, such as the face, neck, hands, and arms. There are several types of cancer that start in the skin. The most common types are basal cell carcinoma and squamous cell carcinoma, which are nonmelanoma skin cancers. Actinic keratosis is a skin condition that sometimes develops into squamous cell carcinoma.

This summary refers to the treatment of nonmelanoma skin cancer and actinic keratosis. Nonmelanoma skin cancers rarely spread to other parts of the body. Melanoma, the rarest form of skin cancer, is more likely to invade nearby tissues and spread to other parts of the body. Refer to the following PDQ summaries for information on melanoma and other kinds of skin cancer:

Melanoma Treatment
Mycosis Fungoides and the Sézary Syndrome Treatment
Kaposi Sarcoma Treatment
Skin color and exposure to sunlight can affect the risk of developing nonmelanoma skin cancer and actinic keratosis.

Risk factors for basal cell carcinoma and squamous cell carcinoma include the following:

Being exposed to a lot of natural or artificial sunlight.
Having a fair complexion (blond or red hair, fair skin, green or blue eyes, history of freckling).
Having scars or burns on the skin.
Being exposed to arsenic.
Having chronic skin inflammation or skin ulcers.
Being treated with radiation.
Taking immunosuppressive drugs (for example, after an organ transplant).
Having actinic keratosis.
Risk factors for actinic keratosis include the following:

Being exposed to a lot of sunlight.
Having a fair complexion (blond or red hair, fair skin, green or blue eyes, history of freckling).
Nonmelanoma skin cancer and actinic keratosis often appear as a change in the skin.

Not all changes in the skin are a sign of nonmelanoma skin cancer or actinic keratosis, but a doctor should be consulted if changes in the skin are seen.

Possible signs of nonmelanoma skin cancer include the following:

A sore that does not heal.
Areas of the skin that are:
Small, raised, smooth, shiny, and waxy.
Small, raised, and red or reddish-brown.
Flat, rough, red or brown, and scaly.
Scaly, bleeding, or crusty.
Similar to a scar and firm.
Possible signs of actinic keratosis include the following:

A rough, red, pink, or brown, raised, scaly patch on the skin.
Cracking or peeling of the lower lip that is not helped by lip balm or petroleum jelly.
Tests or procedures that examine the skin are used to detect (find) and diagnose nonmelanoma skin cancer and actinic keratosis.

The following procedures may be used:

Skin examination: A doctor or nurse checks the skin for bumps or spots that look abnormal in color, size, shape, or texture.
Biopsy: All or part of the abnormal-looking growth is cut from the skin and viewed under a microscope by a pathologist to see if cancer cells are present. There are 3 main types of skin biopsies:
Shave biopsy: A sterile razor blade is used to “shave-off” the abnormal-looking growth.
Punch biopsy: A special instrument called a punch or a trephine is used to remove a circle of tissue from the abnormal-looking growth.
Excisional biopsy: A scalpel is used to remove the entire growth.
Certain factors affect prognosis (chance of recovery) and treatment options.

The prognosis (chance of recovery) depends mostly on the stage of the cancer and the type of treatment used to remove the cancer.

Treatment options depend on the following:

The stage of the cancer (whether it has spread deeper into the skin or to other places in the body).
The type of cancer.
The size and location of the tumor.
The patient’s general health