Inflammation of the skin caused by overexposure to the sun

  • More common in fair-skinned people
  • Outdoor activities are risk factors
  • Age and gender are not significant factors

Sunburn occurs when the ultraviolet rays in sunlight damage cells in the outer layer of the skin, causing soreness, redness, and blistering. Damage is most likely to occur in the middle of the day when the sun is at its highest, but sunlight at any time of day can be harmful. It is possible for sunburn to occur even when the sky is overcast because ultraviolet rays can penetrate the cloud cover. Sunlight reflected off water or snow is especially damaging because its effects are intensified.

Fair-skinned people are more susceptible to sunburn because their skin produces only a small amount of the protective pigment melanin.

Sunburn or long-term exposure to the sun can cause the skin to age prematurely and increase the risk of developing skin cancer. To prevent sunburn and to protect the skin from the damaging effects of ultraviolet (UV) radiation, use sunscreens regularly (see Sunscreens and sunblocks). You should also avoid excessive exposure to the sun (see Safety in the sun).

What are the symptoms?

Sunburn can occur after just 30 minutes of exposing the skin to the sun. The symptoms may take a few hours to develop and include:

  • Sore, red, hot skin.

  • Swelling of the affected area.

  • In severe cases, blistering.

A few days after the initial sunburn, the skin may become dry and start to peel. Severe sunburn may be associated with heatstroke, which is a potentially fatal condition (see Heat exhaustion and heatstroke).


Even a short period of exposure to the sun can damage the surface of the skin, resulting in reddening and soreness.

What is the treatment?

If you develop sunburn, stay in the shade and drink plenty of fluids. You may be able to relieve symptoms by applying aloe-based gels or calamine lotion. Cool baths and compresses may also help. Severe sunburn needs immediate medical attention, and you should consult your doctor as soon as possible. If you are severely burned and you also have heatstroke, you will need urgent treatment in hospital.

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.

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