Clinical Notes : Dermatology

110. Sunburn



  • Sunburn is an acute cutaneous inflammatory reaction that follows excessive exposure of the skin to ultraviolet radiation (UVR).

  • UVR exposure can come from a variety of sources, including (1)

    • sun

    • tanning beds

    • phototherapy lamps

    • arc lamps

  • Most acute sunburns presenting in OOH are classified as superficial or first-degree burns.


  • Short exposure to solar radiation results in

    • stimulation the cutaneous synthesis of vitamin D and providing radiant warmth  (2)

    • increase in skin pigmentation, in 2 phases (9) 

      1. immediate pigment darkening

        • from alteration of existing melanin (oxidation, redistribution)

        • may fade rapidly or persist for several days

      2. delayed tanning

        • from increased synthesis of epidermal melanin

  • Within an hour of UVR exposure

    • mast cells release preformed mediators including histamine, serotonin, and tumor necrosis factor, leading to prostaglandin and leukotriene synthesis (4) 

    • Cytokine release additionally contributes to the inflammatory reaction, with an infiltrate of neutrophils and T lymphocytes.(5)


  • Within 2 hours after UV exposure

    • damage to epidermal skin cells is seen (6)

    • Both epidermal keratinocytes ("sunburn cells") and Langerhans cells undergo apoptotic changes as a consequence of UVR-induced DNA damage (7)


  • Within 3-4 hours after UV exposure

    • Erythema occurs, with peak levels at 24 hours (8).

  • Longer exposure to solar radiation causes

    • direct damage to DNA by UVR, resulting in inflammation and apoptosis of skin cells, manifest as sunburn.(3)

    • vasodilation of cutaneous blood vessels, resulting in the characteristic erythema

    • skin thickening

      • epidermal hyperplasia and

      • thickening of the stratum corneum

    • ​suppression of cutaneous cell–mediated immunity, which might contribute to skin cancer



  • Increased incidence of sunburn is noted with

    • Location (9)

      • closer to the equator

      • higher in altitude

    • Race (10)

      • lighter-skinned individuals 

    • Sex (11)

      • men have a slightly higher prevalence of sunburn than women

    • Age (12)

      • more common in children than in adults

  • Increased UVR induced erythema is dependent on

    • Wavelength (2)

      • UVB is more erythemogenic than UVA.

    • Skin type/pigmentation (13)

      • compared with type I-II skin, patients with type IV-V skin require 3-5 times more UVR exposure to cause erythema

    • Hydration (14)

      • UVR causes erythema in moist skin more effectively than dry skin

    • Environmental reflection (15)

      • radiation is 80% reflected by snow and ice, compared with 15% by sand

    • Ozone coverage (15)

      • increased levels of ozone filter out more UVR

    • Altitude (15)

      • thinner atmosphere at higher altitudes absorbs less UVR

    • Latitude (15)

      • exposure is greater nearer the equator

    • Time of day (15)

      • UVR exposure is greatest from 10 am to 4 pm, when the sun is highest in the sky

    • Season (15)

      • in locations outside the tropics, UVR is much greater in summer than winter

    • Cloud cover (15)

      • light clouds attenuate UVR by 10%, which may not be enough to protect from sunburn


  • Most sunburns, while painful, are not life threatening, and treatment is primarily symptomatic (8)

    • Cool baths or showers

    • Anti-inflammatory/analgesic medications

    • Avoidance of further sun exposure

  • Nonsteroidal anti-inflammatory drugs (NSAIDs) (16)

    • have antiprostaglandin effects and may relieve pain and inflammation, especially when given early

    • do not shorten the duration of sunburn

  • Fluid replacement (oral or intravenous) (17)

    • for severe erythema or concomitant fluid loss


  • Emollients such as aloe vera (16)

    • studies have failed to demonstrate decreased recovery times

    • may help with sunburn symptoms

  • Topical anesthetic sprays or creams

    • may cause sensitization and consequent dermatitis and, therefore, should be avoided (17)


  • Systemic steroids

    • may shorten the course and reduce the pain of sunburn when given early and in relatively high doses (equivalent to 40-60 mg/d of prednisone) (8).  Although this is described in the literature, currently, there is no evidence to support this practice (16)

    • prescribe for only a few days, with no need for a taper.

    • in the presence of partial-thickness (second-degree) burn, steroids are best avoided because they increase the risk of infection. Topical steroids show minimal, if any, benefit (18)


  • Inpatient care (referral to A+E) is indicated for

    • severe burns

    • secondary infection

    • control of severe pain

    • second-degree burns covering (19)

      • 25% of total body surface area in adults

      • 20% of total body surface area in patients aged > 50 y


  • Avoid sun exposure 

    • especially during the period of peak solar radiation (from 10 am to 4 pm) (15)

    • excercise special care when at increased risk (see epidemiology above)

  • Sunscreen

    • use adequate sun protection factor (SPF) for a given skin type

      • SPF is the ratio of the amount of UV energy needed to produce erythema on protected skin to the amount of UV energy needed to produce erythema on unprotected skin (20)

    • Apply at least 30 minutes prior to sun exposure

      • Apply at least 2 mg/cm2 of sunscreen to achieve the advertised SPF (about 30 mL is adequate coverage for an average adult's entire body). Most people apply one fifth of this amount.(21)

    • Reapply every 2-3 hours or after swimming, sweating, or toweling off

    • Use waterproof sunscreen when swimming or perspiring heavily

    • Physical barriers (22)

      • eg, zinc oxide, titanium dioxide

      • provide excellent protection against UVA and UVB and are photostable 

    • Chemical barriers (22)

      • used in most sunscreens.

      • para-aminobenzoic acid (PABA) and PABA esters, UVB blockers,

      • have fallen out of favor because of high rates of associated contact dermatitis and clothing staining.

      • other chemical UVB blocking agents include cinnamates and salicylates 

  • Protective clothing

    • including wide-brimmed hat or sun visor

    • clothing can be treated with over-the-counter products to increase protection from UV radiation (23)

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1. Kochevar IE, Taylor CR.

Photophysics, photochemistry and photobiology. Freedberg IM, ed.

Fitzpatrick's Dermatology in General Medicine. 6th ed. New York, NY: McGraw-Hill; 2003. 1267-1275.

2. Walker SL, Hawk JL, Young AR.

Acute effects of ultraviolet radiation on the skin. Freedberg IM, ed.

Fitzpatrick's Dermatology in General Medicine. 6th ed. New York, NY: McGraw-Hill; 2003. 1275-1282.

3. Matsumura Y, Ananthaswamy HN.

Toxic effects of ultraviolet radiation on the skin.

Toxicol Appl Pharmacol. 2004 Mar 15. 195(3):298-308. 



4. Walsh LJ.

Ultraviolet B irradiation of skin induces mast cell degranulation and release of tumour necrosis factor-alpha.

Immunol Cell Biol. 1995 Jun. 73(3):226-33.


5. Terui T, Takahashi K, Funayama M, Terunuma A, Ozawa M, Sasai S, et al.

Occurrence of neutrophils and activated Th1 cells in UVB-induced erythema.

Acta Derm Venereol. 2001 Jan-Feb. 81(1):8-13.


6. Clydesdale GJ, Dandie GW, Muller HK.

Ultraviolet light induced injury: immunological and inflammatory effects.

Immunol Cell Biol. 2001 Dec. 79(6):547-68.



7. Van Laethem A, Claerhout S, Garmyn M, Agostinis P.

The sunburn cell: regulation of death and survival of the keratinocyte.

Int J Biochem Cell Biol. 2005 Aug. 37(8):1547-53.


8. Kramer DA, Shayne P.

Sun-induced disorders. Schwartz GR, ed. Principles and Practice of Emergency Medicine.

4th ed. Baltimore, MD: Lippincott Williams & Wilkins; 1999. 1581.

9. Narbutt J, Lesiak A, Sysa-Jedrzejowska A, Boncela J, Wozniacka A, Norval M.

Repeated exposures of humans to low doses of solar simulated radiation lead to limited photoadaptation and photoprotection against UVB-induced erythema and cytokine mRNA up-regulation.

J Dermatol Sci. 2007 Mar. 45(3):210-2.


10. Fitzpatrick TB.

The validity and practicality of sun-reactive skin types I through VI.

Arch Dermatol. 1988 Jun. 124(6):869-71.


11. Centers for Disease Control and Prevention (CDC).

Sunburn prevalence among adults--United States, 1999, 2003, and 2004.

MMWR Morb Mortal Wkly Rep. 2007 Jun 1. 56(21):524-8.


12. Cokkinides V, Weinstock M, Glanz K, Albano J, Ward E, Thun M.

Trends in sunburns, sun protection practices, and attitudes toward sun exposure protection and tanning among US adolescents, 1998-2004.

Pediatrics. 2006 Sep. 118(3):853-64.


13. Centers for Disease Control and Prevention.

Sunburn and sun protective behaviors among adults aged 18-29 years--United States, 2000-2010.

MMWR Morb Mortal Wkly Rep. 2012 May 11. 61(18):317-22.


14. Moehrle M, Koehle W, Dietz K, Lischka G.

Reduction of minimal erythema dose by sweating.

Photodermatol Photoimmunol Photomed. 2000 Dec. 16(6):260-2. 


15. World Health Organization.

Ultraviolet radiation: global solar UV index. Fact sheet No. 271. August 2002.


16. Han A, Maibach HI.

Management of acute sunburn.

Am J Clin Dermatol. 2004. 5 (1):39-47.


17 Rapaport MJ, Rapaport V. Preventive and therapeutic approaches to short- and long-term sun damaged skin.

Clin Dermatol. 1998 Jul-Aug. 16(4):429-39.


18. Faurschou A, Wulf HC.

Topical corticosteroids in the treatment of acute sunburn: a randomized, double-blind clinical trial.

Arch Dermatol. 2008 May. 144(5):620-4.


19 Edlich RF, Martin ML, Long WB.

Thermal burns. Marx JA, ed. Rosen's Emergency Medicine:

Concepts and Clinical Practice. 6th ed. Philadelphia, PA: Mosby Elsevier; 2006. 918-9.

20. Gasparro FP, Brown D, Diffey BL, Knowland JS, Reeve V.

Sun protective agents: formulations, effects and side effects.

Freedberg IM, ed. Fitzpatrick's Dermatology in General Medicine. 6th ed. New York, NY: McGraw-Hill; 2003. 2344-2352.

21. Autier P, Boniol M, Severi G, Dore JF,.

Quantity of sunscreen used by European students.

Br J Dermatol. 2001 Feb. 144(2):288-91. 


22. Lowe NJ.

An overview of ultraviolet radiation, sunscreens, and photo-induced dermatoses.

Dermatol Clin. 2006 Jan. 24(1):9-17.


23. Hatch KL, Osterwalder U.

Garments as solar ultraviolet radiation screening materials.

Dermatol Clin. 2006 Jan. 24(1):85-100.



BMJ Best Practice

Las reviewed : February 2019

Last Updated : March 2018


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