Pre-cancer lesions on the skin are scaling, rough growths that appear on areas affected by chronic sun damage. They may appear on the face, neck, arms, a bald scalp, and ears. These lesions can turn into squamous cell carcinomas, one type of skin cancer.

Another word for pre-cancer lesions is actinic keratosis for one or keratoses for many, as they often appear in clusters. The lesions start out very small and grow to about an eight to a quarter of an inch. In the early stages, the keratoses may be invisible to the naked eye but perceptible by touch. As they grow, they scale and may become inflamed. In some cases, they can bleed.

Fair-skinned people are at a greater risk of actinic keratoses because of their sensitivity to sun exposure. Pre-cancer lesions are more likely in older people because of the cumulative effect of years of sun exposure, but they can appear on people in their twenties. Frequent exposure to the sun and to tanning beds can accelerate the damage to the skin, which leads to such lesions.

Once pre-cancerous lesions have been identified, a dermatologist may take some tissue for biopsy to determine if it is cancerous. Not all actinic kertoses become cancerous but there is no way of knowing without testing them. Early identification and removal is the best way to ensure they do not become cancerous. Topical creams and ointments are available that heal the lesions. They may also be frozen off with liquid nitrogen, removed with chemical peels or laser surgery, or eliminated with photodynamic therapy. All of these treatments are designed to remove the lesions before they turn into cancer.

People should check their skin regularly to look for any unusual growths or lesions as they may be pre-cancerous. The best way to prevent actinic kertoses is to wear sunscreen and protective clothing to limit sun exposure.