Actinic keratoses (AKs) are pre-cancerous lesions that most often occur on the face, scalp, hands and arms. These lesions, which can progress to invasive squamous cell carcinoma (SCC), can also occur in the feet. The estimated percentage of actinic keratosis lesions that progress to squamous cell carcinoma is 0.1 percent per lesion per year.
Actinic keratoses are one of the most common skin conditions worldwide, especially among the elderly, fair-skinned and immunocompromised populations. Individuals with extensive sun exposure are at increased risk of developing actinic keratoses. In a population-based study in the United States of patients with a high cumulative sun exposure, actinic keratoses were present in 55 percent of Caucasian men and 37 percent of Caucasian women between the ages of 65 and 74 years. Clinicians frequently find actinic keratoses on sun-exposed areas of the legs and arms, and especially the balding scalp, face, and neck.
As time and sun exposure progresses, the flat actinic keratosis enlarges into elevated bumps that are easily felt. The classic form of actinic keratosis presents as bump that ranges from a few millimeters to two centimeters in diameter. There may be thick, adherent scales on a red base, or they can be smooth, red flat spots. On the face, there can be a “strawberry pattern,” dilated vessels on a background of redness.
Treatments for actinic keratoses include: diclofenac 3% in a 2.5% hyaluronan gel, fluorouracil 5% cream, radiation therapy, photodynamic therapy.
Unfortunately, surveys find that of all body sites, the top of the feet are the least likely sites to receive sunscreen applications. Simply wearing shoes and socks may be an even better way to protect the feet from the sun.