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Medical Professionals

Professional Reference articles are designed for health professionals to use. They are written by UK doctors and based on research evidence, UK and European Guidelines. You may find the Sun and sunburn article more useful, or one of our other health articles.

See the separate related article Burns - Assessment and Management.

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What is sunburn?

Sunburn is a common, acute inflammatory response of skin to exposure to ultraviolet radiation (UVR).

UVR causes vasodilation and release of mast cell mediators, leading to an inflammatory response. Less intense or shorter-duration exposure to UVR leads to increased skin pigmentation (tanning) which provides some protection against further UVR-induced damage.

Sunburn risk factors1

  • Duration of exposure.

  • Height of the sun (greatest exposure at midday, in midsummer and at the equator).

  • Type of UVR: UVB is more potent than UVA, but less prevalent in sunlight.

  • Increasing altitude (less atmospheric filtration).

  • Environmental reflection - eg, rippling sea, white sand. Snow and ice can facilitate sunburn with ambient temperatures below zero.

  • Lack of protective sunscreen or clothing increases the risk. It is possible to burn through light clothing.

  • Lighter skin pigmentation is a factor, whether congenital or acquired. Being suntanned gives protection. Skin type is graded I to VI according to risk of burning.

  • Moist skin increases the risk.

  • Limb skin is relatively more resistant than that of the face, neck and torso. Areas not habitually exposed are more vulnerable.

  • The filtering effect of the atmosphere has an effect. The diminishing ozone layer increases the risk whilst atmospheric pollution reduces it.

  • Areas of vitiligo are susceptible to burning, as are areas of alopecia. People with albinism are very sensitive to sunburn.

  • Photosensitivity - for example, systemic lupus erythematosus, porphyria; drugs such as tetracyclines and many others. Xeroderma pigmentosum and certain other genetic conditions may cause sunburn with minimal sun exposure, due to defective DNA repair.

  • Overuse of sunlamps.

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Symptoms of sunburn (presentation)1

  • The skin is hot and red. It blanches on pressure. It is painful and tender and there may be some oedema.

  • Erythema usually occurs 2-6 hours after exposure and peaks at 12- 24 hours. It resolves over 4-7 days, usually with skin scaling and peeling.

  • With more severe sunburn, vesicles and bullae may form.

  • Systemic symptoms can accompany severe sunburn: there may be headache, chills, malaise, nausea and vomiting.


  • As for any burn - assess the severity and area covered (see box below).

  • Examine the skin for colour change, blisters and capillary refill.

  • Assess degree of pain.

  • Check for dehydration.

  • Look for symptoms/signs of heat exhaustion or heatstroke? For example:

    • High body temperature.

    • Fatigue, weakness, dizziness, fainting, headache.

    • Nausea or vomiting.

    • Rapid pulse.

    • Myalgia.

    • Altered behaviour - irritability, agitation, impaired judgement, confusion, disorientation, hallucinations.

  • In children (as with any burn) consider whether neglect or non-accidental injury could be a cause.

  • Presence of co-existing injuries.

  • Note co-existing or contributing medical conditions.

Important information

Burns are categorised as:23

Superficial epidermal: red and painful, but not blistered.

Partial thickness (superficial dermal): pale pink and painful with blistering.

Partial thickness (deep dermal): dry or moist, blotchy and red, and may be painful or painless. There may be blisters. Capillary refill is absent.

Full thickness: dry and white, brown, or black in colour, with no blisters, no pain and no capillary refill.

Sunburn is usually a superficial epidermal burn but may be partial thickness in severe cases.

The percentage of area burned can be estimated using the 'rule of 9s' (in adults), or by the hand area being 1% of body surface area. Areas of simple erythema are not counted:

The adult body is divided into anatomical regions that represent 9%, or multiples of 9%, of the total body surface. Therefore, 9% each for the head and each upper limb. 18% each for each lower limb, front of trunk and back of trunk.

The palmar surface of the patient's hand, including the fingers, represents approximately 1% of the patient's body surface.

Body surface area differs considerably for children - the Lund and Browder chart takes into account changes in body surface area with age and growth.3

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Who needs referral for sunburn?2

Minor burns, including sunburn, can usually be treated in primary care. Superficial epidermal burns do not need referral. The following patients need referral (usually to A&E in the first instance but may be referred to a burns unit, depending on local protocols):

  • All deep dermal and full-thickness burns.

  • All circumferential burns (those that go all the way round a part of the body).

  • Superficial dermal burns of more than 3% total burn surface area (TBSA) in those aged ≥16.

  • Superficial dermal burns of more than 2% TBSA in under-16s.

  • Superficial dermal burns involving the face, hands, feet, perineum, genitalia or flexures.

  • Suspicion of dehydration, heatstroke, shock or sepsis.

  • Suspicion of non-accidental injury or neglect.

Referral should also be considered in the following scenarios:

  • Young or old: children aged <5 years, adults aged >60 years.

  • Co-existing medical problems (eg, cardiac, respiratory or hepatic disease; diabetes; immunosuppressed; pregnancy).

  • Needing admission for social reasons, pain control or if dressings are difficult to manage.

  • Uncertainty about the depth or severity of the burn.

  • Other injuries.

  • A wound that has not healed 14 days after injury.

Differential diagnosis

The cause is usually clear from the history, but consider:

Sunburn treatment and management2

Mild-to-moderate sunburn

  • The vast majority of sunburn is superficial and spontaneously resolves.

  • Maintain adequate hydration.

  • Symptoms may be relieved by:

    • A cool shower or cool compresses.

    • Simple analgesics (paracetamol or ibuprofen).

    • Emollients.


Some sources suggest that oral non-steroidal anti-inflammatory drugs (NSAIDs) and/or topical steroids reduce erythema.1 However, one small trial and reviews of the literature have been less enthusiastic.6 One review found that the overall opinion was that corticosteroids, NSAIDs, antioxidants, antihistamines or emollients were ineffective at decreasing recovery time.7 The remaining studies showed mild improvement with such treatments; however, study designs or methods were flawed. Furthermore, regardless of the treatment modality, the damage to epidermal cells is the same. Topical anaesthetics are not recommended.


Treatment should be as for any other severe burn. See the separate Burns - Assessment and Management article.


Sunburn prevention1 8

Sufficient exposure to sunlight is essential for adequate vitamin D levels and to avoid vitamin D deficiency. Therefore a balance must be struck between the benefits of sunshine for vitamin D status and the adverse effects of excessive sun exposure such as the risk of sunburn and increasing skin cancer rates.

Sunburn is better prevented than treated. Sun protection is the best defence against sunburn and other damaging effects of UVR:

  • Avoid sun exposure, especially between 11 am to 3 pm.

  • Wear protective clothing, including wide-brimmed hats.

  • Apply adequate amounts of sunscreen with a sun protection factor (SPF) of ≥15. Use a sunscreen with both UVA and UVB protection. Higher minimum factor sunscreen may be advised outside the UK.

  • Use a generous amount of sunscreen. Ideally, apply it half an hour before exposure. Reapply regularly. Reapply after being in water, even if sunscreen claims to be water-resistant.


A sunscreen of at least sun protection factor (SPF) 30 (SPF 50 for children) should be used for sun protection.

The safest advice with regard to how much sunscreen to use is "apply liberally". Different products require different amounts so attempts to suggest a standard formula are confusing and not necessarily accurate.

The SPF protection offered by a sunscreen indicates how many times longer a user can stay in the sun compared with the individual without the sunscreen - eg, a cream with SPF 15 can stay 15 times longer. This is calculated with an application thickness of 2 mg/cm2. Unfortunately, sunscreen is very often applied much less than this, typically between 0.5 to 1 mg/cm2, giving a sunscreen labelled SPF of 15 a true SPF of 2-4.

Perhaps a better way of thinking about the SPF is that wearing a sunscreen with a given SPF reduces the UV dose to 1/SPF of that which would be received by spending the same time in the sun but with no sunscreen applied - eg, SPF 15 sunscreen results in a UV exposure to the skin of one-fifteenth of that which would be received without any sunscreen.

The degree of protection against UVA is hard to quantify and is usually much less than protection against UVB.

Concomitant use of insect repellents that contain N,N-diethyl-3-methylbenzamide (DEET) also decreases SPF.

Water-resistant sun protection lotions last longer than others but even they get washed off by sweat and swimming and need to be replaced.

The Met Office provides a UV section with their weather forecasts, with advice on appropriate precautions.9

Further reading and references

  1. Sunburn; DermNet NZ
  2. Burns and scalds; NICE CKS, September 2020 (UK access only)
  3. Enoch S, Roshan A, Shah M; Emergency and early management of burns and scalds. BMJ. 2009 Apr 8;338:b1037. doi: 10.1136/bmj.b1037.
  4. DeVore KJ; Solar burn reactivation induced by methotrexate. Pharmacotherapy. 2010 Apr;30(4):123e-6e.
  5. Goldfeder KL, Levin JM, Katz KA, et al; Ultraviolet recall reaction after total body irradiation, etoposide, and methotrexate therapy. J Am Acad Dermatol. 2007 Mar;56(3):494-9. Epub 2006 Dec 20.
  6. 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.
  7. Han A, Maibach HI; Management of acute sunburn. Am J Clin Dermatol. 2004;5(1):39-47.
  8. Skin cancer prevention: information, resources and environmental changes; NICE Public Health Guideline (January 2011 - last updated February 2016)
  9. UV forecast; Met Office

Article history

The information on this page is written and peer reviewed by qualified clinicians.

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