Effects of Sun on the Skin

Effects of Sun on the Skin 

UV exposure causes thickening and thinning of the skin. Thick skin is found in coarse wrinkles especially on the back of the neck that do not disappear when the skin is stretched.

Blood Vessel Changes Caused by the Sun
 

UV radiation causes the walls of blood vessels to become thinner leading to bruising with only minor trauma in sun-exposed areas. For example, most of the bruising that occurs on sun-damaged skin occurs on the backs of the hands and forearms not on the inside of the upper arm or even the inside of the forearm. The sun also causes the appearance of iny blood vessels, in the skin especially on the face.

UV radiation causes an increased number of moles in sun-exposed areas. Sun exposure also causes precancerous lesions called actinic keratoses that develop especially on the face, ears, and backs of the hands. The are small crusty bumps that can often be felt better than they can be seen. Actinic keratoses are felt to be premalignant lesions because 1 in 100 cases per year will develop into UV exposure also causes, which are warty looking lesions that appear to be "stuck on" the skin. In contrast to actinic keratoses, seborrheic keratoses do not become cancerous.