WHAT CAUSES ACTINIC KERATOSES?

Repeated, prolonged sun exposure causes skin damage, especially in fair-skinned persons. Patients often wonder how they could develop sun-related skin damage when they don't recall any recent substantial sun exposure, but small amounts of cumulative sun damage over a lifetime result in these changes. Sun-damaged skin becomes dry and wrinkled and may form pink or red rough, scaly spots called actinic keratoses. These rough spots remain on the skin even though the crust or scale is picked off. Treatment o actinic keratoses requires removal of the defective skin cells. New skin then forms from the deeper skin cells, which have escaped sun damage.

WHY TREAT ACTINIC KERATOSES?

Actinic keratoses are not skin cancers. Because the thicker or more persistent ones rarely can turn cancerous, we remove them. The overall risk of progression to skin cancer is estimated at 0.25 – 16% per year. It is especially high in patients who are immunosuppressed or have high cumulative sun exposure.

TREATMENT

Actinic Keratoses can be removed surgically with a scraping instrument called a curette. Another way of destroying actinic keratoses is to freeze them with liquid nitrogen, which is the method commonly used. Freezing causes blistering and shedding of sun-damaged skin. When actinic keratoses are frozen, the scab normally falls off in 1-2 weeks. Sometimes we're not sure whether the growth is harmless. When this occurs, we may prefer to cut the growth off and send it for microscopic analysis (biopsy). Healing after removal usually takes two to four weeks, depending on the size and location of the keratoses. Hands and legs heal more slowly that the face. The skin's final appearance is usually excellent.

When there are many keratoses, a useful treatment is the application of 5-fluorouracil (5-FU). The medication is applied on the keratoses for 10 to 30 days. 5-FU destroys sun-damaged skin cells. After three to five days the treated area starts to get raw. The applications are continued until your physician determines that you have the needed results. Healing starts when the 5-FU is stopped. 5-FU is effective in removing actinic keratoses from the face, but it often fails when used on the hands, forearms, or back.

Another useful treatment is the application of a topical cream called imiquimod (Aldara). This cream stimulates the immune system to fight the damaged cells. The cream is applied to the spots once a day, 2 times a week (i.e. Mon & Thurs or Tues & Fri). Treatment is for 4-16 weeks. The sites can become red and sore during the treatment.

PREVENTION

Sun damage is permanent. Once sun damage has progressed to the point where actinic keratoses developed, new keratoses may appear even without further sun exposure. You should avoid excessive sun exposure – but don't go overboard and deprive yourself of the pleasure of being outdoors. Reasonable sun protection should be your aim.

The American Academy of Dermatology is an excellent resource for current information on the sun and your skin www.aad.org/skincnrUpdates.html