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Sunburn and Heat Exposure

Sunburn is a common acute inflammatory response of skin to exposure to ultraviolet radiation (UVR). It is a burn like any other burn except that it tends to be less severe and more widespread than others.

Risk Factors

• Duration of exposure
• Height of the sun. It is higher nearer the middle of the day, the nearer to mid-summer and the lower the latitude.
• Type of UVR: UV-B more potent than UV-A, but less prevalent in sunlight.
• Increasing altitude (less atmospheric filtration)
• Environmental reflection. A rippling sea can increase reflection very significantly as can white sand. Snow and ice can facilitate sunburn with ambient temperatures below zero.
• Lack of protective sunscreens, whether sun protection lotions or clothes. It is possible to burn through light clothes.
• Lighter skin pigmentation, congenital or acquired. Being sun tanned gives protection. Skin type is graded I to VI according to risk of burning.
• Moist skin
• Limb skin relatively more resistant than that of face, neck & torso. Areas not habitually exposed are more vulnerable.
• Filtering effect of the atmosphere. Diminishing ozone layer increases risk whilst atmospheric pollution reduces it.
• Areas of vitiligo are susceptible to burning as are areas of alopecia. Some diseases such as SLE are associated with photosensitivity that may lead to sunburn as may drugs like tetracyclines. People with albinism are very sensitive to sunburn.
• Sunburn can also occur from injudicious use of sunlamps

Presentation

• There may be little response immediately but within a few hours the skin is hot and red but blanches on pressure. It is painful and tender and there may be some oedema.
• In more severe burns, vesicles and bullae may form.
• Systemic symptoms can accompany severe burns with headache, chills, malaise +/- nausea & vomiting.

Investigations

• Generally not required unless very severe. Consider dehydration and raised core temperature.

Management  

• Prevention ¹: 
  • Avoidance of prolonged sun exposure. 
  • Correct use of appropriate factor sunscreens or barrier creams (zinc oxide, titanium dioxide). Measure correct dose using Surface Area Calculator.
  • Burns are caused by heat and can be reduced by periodic cooling such as swimming. Remember that it is still possible to burn whilst swimming.
• Mild sunburn: 
  • Vast majority of sunburn is superficial and spontaneously resolves. Cool soaks
  • NSAIDs may be used. Topical diclofenac sodium has been shown to reduce pain and erythema.³
• Moderate: 
  • As per mild, and:
  • Oral NSAIDs and topical steroids have been reported to have a synergistic effect in reducing erythema.⁴ However, reviews of the literature have been less enthusiastic. One found that the overall opinion was that corticosteroids, NSAIDs, antioxidants, antihistamines or emollients were ineffective at decreasing recovery time. The remaining studies showed mild improvement with such treatments, but study designs or methods were flawed. Furthermore, regardless of the treatment modality, the damage to epidermal cells is the same.⁵
  • Topical anaesthetics are not recommended.
• Severe: 
  • Normal burns protocol

Complications

• Exacerbation of dermatological conditions (Normal burns protocol, Normal burns protocol, etc).
• Premature aging, solar keratoses, basal cell carcinoma, squamous cell carcinoma of skin and malignant melanoma.
• Maybe associated with heatstroke or other heat-related illnesses.
• Photosensitivity reactions.

Prevention:

• Being sensible about not spending too long in the sun without adequate protection is important and education can help this but in the UK there is still a long way to go.⁶
• Water resistant sun protection lotions last longer than others but even they get washed of by sweat and swimming and need to be replaced.
• Planned sunbathing should be a graded and realistic activity
• There is evidence that vitamin C and, to a lesser extent, vitamin E give some protection against burning but this was an experiment on pig skin.⁷

References Used

1. Diffey B; Has the sun protection factor had its day?;BMJ 2000 Jan 15;320(7228):176-7.[full text]
2. Halls BSA web calculator (more extensive calculator which can use other equations)
   Mosteller Method : BSA (m²) = ( Height(cm) x Weight(kg) / 3600 )^½
   e.g. BSA = squareroot of (height (cm)x weight (kg)/3600)
3. Magnette J, Kienzler JL, Alekxandrova I, et al; The efficacy and safety of low-dose diclofenac sodium 0.1% gel for the symptomatic relief of pain and erythema associated with superficial natural sunburn.;Eur J Dermatol 2004 Jul-Aug;14(4):238-46.[abstract]
4. Driscoll MS, Wagner RF Jr; Clinical management of the acute sunburn reaction.;Cutis 2000 Jul;66(1):53-8.[abstract]
5. Han A, Maibach HI; Management of acute sunburn.;Am J Clin Dermatol 2004;5(1):39-47.[abstract]
6. Miles A, Waller J, Hiom S, et al; SunSmart? Skin cancer knowledge and preventive behaviour in a British population representative sample.;Health Educ Res 2005 Oct;20(5):579-85. Epub 2005 Jan 11.[abstract]
7. Darr D, Dunston S, Faust H, et al; Effectiveness of antioxidants (vitamin C and E) with and without sunscreens as topical photoprotectants.;Acta Derm Venereol 1996 Jul;76(4):264-8.[abstract]

Acknowledgements EMIS are grateful to the Mentor authoring team for updating this record from an original by Dr Adrian Bonsall. Calculator by Dr Huw Thomas. The final copy has passed peer review of the independent Mentor GP authoring team. ©EMIS 2006.

Last issued 14 Feb 2006