Actinic keratoses (AKs) are precancerous skin growths. They are sometimes referred to as solar keratoses because sun (solar) exposure is a major risk factor for developing them. Patients often incorrectly self-diagnose them as dry skin that “comes and goes.” AKs appear as a rough, red, scaly patch, bump, or horn on the skin. AKs are commonly found on body areas that are exposed frequently to sun (face, scalp, ears, nose, neck, arms, back of hands, lower legs). AKs are often felt before they are able to be seen. These spots may not have visible symptoms, but often have a burning, sensitive, or painful sensation when touched. Approximately 10% of AKs develop into squamous cell carcinoma (SCC), the second most common form of skin cancer.
Actinic keratosis is directly related to one’s lifetime exposure to the sun or UV radiation. Men are more likely to develop AKs. Actinic keratosis usually present in ages 50 and beyond, but it is not unusual for someone in their 20s or 30s to develop AKs if they have a history of heavy cumulative sun or UV exposure or multiple intermittent sunburns.
When actinic keratoses occur on the lips, it is referred to as “actinic cheilitis.” Actinic cheilitis appears as if the bottom lip but not the top lip is chapped. This occurs because the bottom lip faces the sum whereas the upper lip faces downwards and away from the sun. The lips are more high risk of becoming squamous cell carcinoma so they are even more important to pay attention to and treat.
Actinic Keratoses should be treated to prevent their transformation to squamous cell carcinoma in 10% of cases. The most common treatment is cryotherapy or cryosurgery, which involves freezing the skin with liquid nitrogen. Topical therapies are also an option and names of these include 5-fluorouracil (5-FU, Tolak, Fluoroplex, Carac), imiquimod (Aldara, Zyclara), ingenol mebutate (Picato) and diclofenac (Solaraze). These creams treat visible lesions as well as microscopic lesions that cannot yet be detected. PDT or photodynamic therapy is a means of treating an entire face a for AKs. This procedure combines a topical solution (aminolevulinic acid) that is activated by various laser and light technologies to target precancerous lesions. Chemical peeling also decreases the skin burden of actinic keratoses but is not covered by insurance.
Any suspicious lesions that do not respond to the above treatments may be biopsied to rule out an early skin cancer. The use of sunblock and proper sun protection is critical in preventing new actinic keratosis lesions. Topical retinoids are an ideal daily treatment that can be used to reduce the number of AK lesions that develop over time.