Sun Exposure

AAP Recommendations on Sun Exposure

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Sun Exposure

1)     Damage to skin comes from ultraviolet radiation (UVR)

a)     UVA1 (340-400 nm), UVA2 (320-340 nm), and UVB (290-320 nm)

i)      UVB: Most sunburn and damage to DNA is caused by UVB, but longer wavelength UVA light also contributes

(1)   SPF is the ratio of time the skin is protected from UVB when covered in sunscreen vs unprotected

(a)   e.g. if normal skin burns after 10 minutes, correctly-applied SPF 15 should provide 150 minutes of protection

(b)   Choose a sunscreen of at least SPF 15-30

ii)     UVA: Most sunscreens sold are most effect at blocking UVB, while sunscreen labeled ‘broadspectrum’ also blocks some UVA rays

(1)    Measurements of UVA protection are not standardized in industry

b)     Tanning beds cause the same negative outcomes as solar exposure

c)     Short-term negative effects of UVR exposure

i)      Immunosuppression in the skin

ii)     Sunburn (solar dermatitis), blistering

(1)   Symptomatic treatment: analgesics, cool cloths, aloe vera or emollient

iii)   Photokeratitis, solar retinopathy

d)     Long-term negative effects of UVR exposure

i)      Premature aging of skin: damage to collagen causes decreased elasticity; permanent pigmentation changes

ii)     Skin cancer (because UVR damages DNA): melanoma, basal cell carcinoma (BCC), squamous cell carcinoma (SCC) all linked to sun exposure

(1)   Sunscreen usage decreases the rates of SCC and its precursor lesion actinic keratosis

(2)   Unclear evidence for effect of sunscreen on BCC or melanoma

iii)   Cataracts 

Over 30% of adults and over 70% of adolescents report at least one sunburn in the last year.  The mechanism of sunburn is not fully understood but is thought to involve a cytokine response to DNA damage.  The presentation of sunburn can range from painless erythema to painful and edematous blistering erythema.  The erythema typically peaks between 12 and 24 hours and fades by 72 hours.

 

Skin Cancer

UV DNA damage can result in malignant transformation with an increased risk for squamous cell carcinoma, basal cell carcinoma, and melanoma.  Cumulative sun exposure is the most important cause of squamous cell carcinoma, while intense intermittent sun exposure (such as with sunburn) is the most important risk factor for basal cell carcinoma and melanoma.  The regular use of SPF 15 reduces the risk of skin cancer by 78%.

 

Prevention

a)     Physical means

i)      Sunscreen—consists of compounds which absorb (organic compounds) or reflect (zinc oxide, titanium dioxide) UVR

(1)   Choose SPF > 15; typically SPF 30 is a good choice

(2)   Apply about 30 mL for an adult, 15 minutes before sun exposure

(a)   Insufficient amount of sunscreen leads to a decrease in SPF protection provided

(3)   Reapply every 2-3 hours or after swimming

ii)     Shade – due to scatter of light, sunburn can still occur in the shade

iii)   Long sleeves/hats/sunglasses

(1)   Finely woven or dark colored clothing is most effective at blocking UVR

iv)    Timing

(1)   Avoid sun exposure in the middle of the day (11 am -3 pm) when UVB is strongest

v)     Special note for infants < 6 mo

(1)   Choose shade, long sleeves, and hats to protect infants under 6 months

(2)   If the baby must be exposed to sun, may use a small amount of sunscreen

 

Treatment

The current treatment for sunburn is merely symptomatic and begins with the avoidance of any further sun exposure.  NSAID’s may be used as an analgesic, and the application of topical emollients or aloe vera gel may ease the discomfort.  Cool compresses and soaking in cool water may also provide relief.  If ruptured blisters are present, the cutting away of loose edges may be warranted.

 

Counseling

i)      No adverse effects have been noted from counseling interventions from pediatricians

ii)     Some studies have found improved sun-protection behavior in counseled patients

iii)   Addressing concerns about protection from sun exposure

(1)   Skin reactions (from sunscreen) not common

(a)   Itching, burning, stinging

(b)   Allergic contact dermatitis, phototoxic reactions (rare)

(2)   Evidence for vitamin D deficiency due to sun avoidance is not convincing

(a)   NHANES study found that decreased vitamin D levels were associated with  frequent use of shade or long sleeves , but not the use of sunscreen

(b)   Recommend dietary vitamin D supplementation rather than purposeful sun exposure

(3)   Use of sunscreen does not seem to encourage people to stay in the sun longer

(4)   No evidence that BMI increases as a result of counseling about sun exposure

(a)   Be careful to balance instructions about physical activity with recommendations to limit sun exposure

References

  1. Matsumura, Y, Ananthaswamy, HN. Toxic effects of ultraviolet radiation on the skin. Toxicol Appl Pharmacol 2004; 195:298.
  2. Edwards, EK Jr, Edwards EK, Sr. Sunburn and sunscreens: an update and review. Mil Med 1990; 155:381.
  3. Armstrong, BK, Kricker, A. The epidemiology of UV induced skin cancer. J Photochem Photobiol B 2001; 63:8.
  4. Driscoll, MS, Wagner, RF Jr. Clinical management of the acute sunburn reaction. Cutis 2000; 66:53.
  5. Stokes, R, Diffey, B. How well are sunscreen users protected? Photodermatol Photoimmunol Photomed 1997; 13:186.
  6. Olson AL et al. Solar Protection of Children at the Beach. Pediatrics. 1997; 99(6):e1.
  7. Johnson et al.  Sun Protection Practices for Children Archives of Pediatrics and Adolescent Medicine Vol 155 pg 891 August 2001
  8. Berenberg M, Surbert C. Children and Sun Protection. British Journal of Dermatology 2009 161 (supplement 3) pp33-39.
  9. Paller A et al.  New Insights about Infant and Toddler Skin:  Implications for Sun Protection.  Pediatrics July 2011

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