Sunburn

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.

• Duration of exposure is proportional to risk.
• The height of the sun is significant: it is higher nearer the middle of the day, the nearer to mid-summer and the lower the latitude.
• Type of UVR: UV-B is more potent than UV-A, but less prevalent in sunlight.
• Increasing altitude results in 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 increases the risk, whether sun protection lotions or clothes. It is possible to burn through light clothes.
• Lighter skin pigmentation is a factor, whether congenital or acquired. Being sun tanned 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 & 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. Some diseases such as systemic lupus erythematosus 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.

• 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.

These are generally not required unless very severe. Consider dehydration and raised core temperature.

Mild sunburn

The vast majority of sunburn is superficial and spontaneously resolves. Cool soaks and nonsteroidal
anti-inflammatories (NSAIDs) may be helpful. Topical diclofenac sodium has been shown to reduce pain and erythema.²

Moderate

Some studies suggest that a combination of oral NSAIDs and topical steroids have a synergistic effect in reducing erythema.³ 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.⁴Topical anaesthetics are not recommended.

Severe

Treatment should be as for any other severe burn.

• Exacerbation of dermatological conditions
• 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

• Patients should be advised to be sensible about not spending too long in the sun without adequate protection. Education can help this but in the UK there is still a long way to go.⁶
• Correct use of appropriate factor sunscreens or barrier creams should be advised (zinc oxide, titanium dioxide).⁷ The correct dose can be calculated using the Surface Area Calculator.⁸
  The sun protection factor (SPF) protection offered by a sunscreen indicates how many times longer an user can stay in the sun compared with the individual without the sunscreen - e.g. a cream with SPF15 can stay 15 times longer. This is calculated with an application thickness of 2 mg/cm². Unfortunately consumers apply much less than this, typically between 0.5 to 1.3 mg/cm².⁵
• 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.
  Water resistant sun protection lotions last longer than others but even they get washed of by sweat and swimming and need to be replaced.
• Studies using a combination of vitamin C and E offers significant photoprotection but this study was done on pig skin, and further evaluation needs to be carried out in humans.⁹