MODEL RELEASED. Sunburnt skin on a man's shoulders. Sunburn is caused by over exposure to sunlight. The ultraviolet radiation in sunlight destroys cells in the skin's outer layer and damages tiny blood vessels beneath. Affected skin becomes inflamed and may blister. Several days later the dead cells are shed in a peeling process. Sunburn is most common in fair-skinned people, whose skin lacks the protective pigment melanin. Repeated exposure can age the skin prematurely and increases the risk of skin cancer. Calamine lotion and painkillers can help to soothe sunburnt skin, but severe cases require medical attention and corticosteroid drugs.