Actinic keratosis, also known as a solar keratosis, is a scaly or crusty bump that arises on the skin surface. The base may be light or dark, tan, pink, red, a combination of these, or the same color as the skin. The scale or crust is horny, dry and rough, and is often recognized by touch rather than sight. Occasionally, it itches or produces a pricking or tender sensation.
Actinic keratosis can be the first step in the development of skin cancer and, therefore, is considered a precancerous skin condition. The presence of actinic keratoses indicates that sun damage has occurred and that any kind of skin cancer can develop.
How does an actinic keratosis develop?
An actinic keratosis develops slowly and most likely appears on the face, ears, bald scalp, neck, backs of hands and forearms, and lips. It tends to lie flat against the skin of the head and neck, but appear elevated on arms and hands. Often, a person will have more than one actinic keratosis lesion.
The lesions are usually not life threatening, provided they are detected and treated in the early stages. However, if this is not done, they can grow large and invade the surrounding tissues and, on rare occasions, metastasize or spread to the internal organs.
The most aggressive form of keratosis, actinic cheilitis, appears on the lips and can evolve into squamous cell carcinoma. When this happens, about 20 percent of these carcinomas metastasize to other parts of the body.
It is estimated that up to 10 percent of active lesions, which are more red in color and more tender than the rest, will take the next step and progress to squamous cell carcinomas.
What causes actinic keratosis?
Sun exposure causes almost all actinic keratoses. Sun damage to the skin accumulates over time, so that even a brief exposure adds to the lifetime total. Certain groups of people are more at risk than others, including the following:
- People who have fair skin, blonde or red hair, and blue, green or gray eyes are at the greatest risk, but darker-skinned people can develop keratoses if they expose themselves to the sun without protection.
- African Americans rarely have these lesions.
- Individuals who are immunosuppressed as a result of cancer chemotherapy, AIDS or organ transplantation also are at higher risk.
One in six people will develop an actinic keratosis in the course of a lifetime, according to some estimates. Older people are more likely than younger people to develop actinic keratoses, because cumulative sun exposure increases with age.
Treatment for actinic keratosis
Specific treatment for actinic keratosis will be determined by your physician based on:
- Your age, overall health and medical history.
- Extent of the disease.
- Your tolerance for specific medications, procedures or therapies.
- Expectations for the course of the disease.
- Your opinion or preference.
When diagnosed early, treatment for actinic keratosis may include cryotherapy (freezing the lesion), topical chemotherapy (anti-cancer drugs) or other treatments.