Actinic keratosis is a common premalignant skin lesion seen on areas of the body that have been exposed to sun. Premalignant means that the lesions have the potential to become skin cancer, but have not yet done so.
Sun damage over many years causes changes in the skin. When the cells start to grow in an irregular and unusual fashion, actinic keratosis may develop. The lesions are not true deep or invasive skin cancers, but the area of skin is no longer normal.
The skin lesions of actinic keratosis start out as flat, scaly, red patches. These patches are seen on areas of the skin that are exposed to the sun. They are dry, horny, and rough. The lesions are often felt more easily than they are seen. Sometimes the lesions may be tender or cause itching.
The lesions grow slowly and range from 1/8 to 1/4 inch in diameter. They may go away and return at a later time. Over time, the lesions may change to wartlike white, hard crusts. Common locations for the lesions include: backs of hands and forearmsbald scalpface and earslipsneck
Actinic keratosis is caused by long-term exposure to the sun. The number of lesions increases with age. A person with light skin has a higher risk of developing actinic keratosis. Someone who works outdoors, such as a lifeguard or construction worker, is at greater risk. Certain antibiotics, such as tetracycline, increase a person's risk.
People with altered immune systems are also at increased risk for actinic keratosis. This group includes: people with HIV infection or other acquired immunodeficiency disorderschildren born with immunodeficiency disordersindividuals who are taking powerful immunosuppressive medicines after organ transplantspersons who are taking chemotherapy for treatment of cancer or other disorders
Actinic keratosis can be prevented by using skin cancer prevention techniques. A person should limit time in the sun, especially during the middle of the day. Regular use of sunscreen outdoors helps prevent actinic keratosis. Protective clothing, such as a hat and long sleeves, will also help. Tanning parlors and artificial tanning machines should be avoided.
Diagnosis of actinic keratosis begins with a medical history and physical exam. A biopsy may be performed to confirm the diagnosis. This involves taking a sample of the skin from the affected area and examining it under a microscope.
Between 10% and 20% of actinic keratosis lesions will become skin cancer over time. The lesions may also be painful or cosmetically embarrassing.
Actinic keratosis is not contagious and poses no risk to others.
Treatments for actinic keratosis include: chemical peeling, which uses trichloroacetic acid or phenol to cause the top layer of skin to slough offcryosurgery, which uses extreme cold to destroy abnormal cellscurettage and desiccation, which involves scraping of the lesion followed by electrocautery to control bleedingdermabrasion, which involves sanding off the top layers of the lesionlaser surgery, which removes the lesionsshave removal with a scalpel, followed by electrocautery to stop bleedingtopical medicines, such as 5-fluorouracil(i.e., Adrucil, Efudex, Fluoroplex) or masoprocol (i.e., Actinex), which remove the lesions
Medicines may cause loss of pigmentation in the treated skin area or allergic reactions. Surgery can be complicated by bleeding, infection, or reactions to anesthesia.
After treatment, the sites usually heal into smooth skin and are unnoticeable. The person will still have a tendency to develop precancerous lesions. The person should follow skin cancer prevention guidelines for the rest of his or her life.
A person with actinic keratosis is much more likely to have true skin cancer than most people. He or she should visit the healthcare
Skin Disorders: Mosby's Clinical Nursing Series, MJ Hill, 1994
Harrison's Principles of Internal Medicine, Fauci et al, 1998