Sunburn is skin damage caused by ultraviolet (UV) rays in sunlight. Too much exposure to UV light causes skin to overheat resulting in it becoming red and painful. It may also peel or blister.
When your skin is exposed to sunlight, it produces a pigment called melanin which helps protect itself against the UV rays. This is also what makes the skin darken in colour, producing a sun tan.
Sunburnt skin becomes red and sore. It will be warm to the touch, even following attempts to cool it. After a few days, the redness may fade into a tan or in very fair people, where melanin levels are considerably lower, the skin may just return to white.
The skin may also flake or peel after a few days. This is how the body protects itself. The skin cells that have been damaged and are at risk of becoming cancerous are shed by the body.
Dark skin can also burn and become damaged if exposed to enough UV light. However, as it contains more pigment, it can tolerate sunlight without burning longer than fairer skin can.
The symptoms of sunburn are not usually immediately obvious. The worst pain occurs between 6 and 48 hours after being exposed to the sun.
Severe sunburn can cause:
Swelling of the skin
There may also be symptoms of heatstroke, such as: