Sunburn causes:

Being sunburnt results from too much sun exposure. Most people has been sunburnt at some point in their life due to being out in the sun for too much. This means anyone who goes to the beach, fishing, working in the yard and going on holiday etc.

Sunburn is a burn of your skin which peels. It's a ultra-violet radiation and the result of this burn is because the skin has has inflammation.

• UVA and UVB refer to different wavelengths in the light spectrum. UVB is more damaging to the skin especially for skin cancer. Both UVA and UVB are responsible for photoaging (premature aging of the skin and wrinkles) and sunburn. Tanning beds produce both UVA and UVB rays.

• Travel to the southern United States, regions close to the equator, and places at high altitudes all offer the unwary visitor an opportunity to be injured by sunburn.

• Certain light-skinned and fair-haired people are at greater risk of sunburn injury.

• Prior recent sun exposure and prior skin injury are risks for sunburn, even in limited exposure to the sun. However, normal limited exposure to UV radiationproduces beneficial vitamin D in the skin

(source: http://www.emedicinehealth.com/sunburn/article_em.htm)