Do aks grow without sun?

AKs. Chronic sun exposure is the cause of almost all actinic keratoses. Sun damage to the skin is cumulative, so even a brief period in the sun adds to the lifetime total. Cloudy days aren’t safe either, because 70-80 percent of solar ultraviolet (uv) rays can pass through clouds. These harmful rays can also bounce off sand, snow and other reflective surfaces, giving you extra exposure.