Actinic keratoses (AKs), are precancerous lesions most often caused by sunlight. They typically feel rough and may come and go for months before staying consistently. This is because your immune system tries to eliminate the lesion but is ultimately overpowered.

Actinic keratoses are the beginning of squamous cell carcinoma skin cancers. Left untreated, AKs can progress to invasive squamous cell carcinoma, a common form of skin cancer. While AKs are often cosmetically unattractive, treatment is primarily aimed at eliminating them to prevent dangerous squamous cell carcinomas.

Clinically diagnosed AKs may be treated by cryosurgery (freezing), curettage (scraping), topical medications, laser treatment, chemical peels, dermabrasion, or photodynamic therapy. An AK that has advanced to a borderline squamous cell carcinoma may be excised.

Sun damaged stem cells are not fixed when AKs are removed, so as abnormal cells repopulate the skin surface, AKs form again. This means that treated AKs tend to recur over time.  For this reason routine examinations are necessary, and treatment of AKS must continue as needed.