Causes of Actinic Keratosis
Prolonged exposure to the sun causes scaly patches on the face and body, which range in size from a pencil point to its eraser. There is sometimes a prickling pain with the patches. Others at risk of contracting the scaly patches include those whose immune systems have been suppressed due to organ transplants, and psoriasis patients treated with an ultraviolet light therapy along with the drug psoralen.

It takes years, even decades, for the patches to suddenly appear from nowhere. Unfortunately, they are precancerous. While a relatively small percentage of people with that kind of sun exposure might be likely to develop skin cancer, the risk can be decreased further by making sure to take preventative measures. Some types of skin cancer are destructive to the body area in which they live, but they do have a chance to spread, which makes them dangerous.