Dermatology Book

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SunscreenAka: Sun Protection Factor

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  1. See Also
    1. Sun Exposure (lists other preventive measures)
    2. Sun Damaged Skin
    3. Phototoxic Reaction
    4. Sunburn
  2. Recommendations
    1. Use sunscreen with SPF of 15 or higher
    2. Use sunscreen that blocks UVA and UVB
      1. Most current sunscreens block UVB
      2. SPF rating does not apply to UVA
      3. Zinc Oxide, Titanium dioxide, Mexoryl block UVA
    3. Shake sunscreen well before using
    4. Wear sunscreen on all outdoor daylight exposures
      1. Cloudy days: 80% UV radiation penetrates clouds
      2. Swimming: 50% UV radiation penetrates water
      3. High altitude (UVB increases 8-10% per 1000 feet)
      4. Exposure to snow or water (reflective surface)
    5. Apply 1 ounce of sunscreen for whole body
      1. Do not forget around eyes, ears and mouth
      2. Apply to scalp if bald or hair thinning
    6. Reapply sunscreen hourly when sweaty or wet
    7. Protect babies and children well from Sun Exposure
  3. Physiology
    1. Sun Protection factor (SPF) ratio
      1. Time to produce slight erythema on suncreened skin to
      2. Time to produce same erythema without sunscreen
    2. SPF Interpretation
      1. SPF gives no information on Ultraviolet A protection
  4. Preparations: Organic Sunscreens
    1. Avobenzone (Parsol 1789)
      1. Absorbs both short and long wavelength Ultraviolet A
      2. Does not absorb Ultraviolet B (UVB)
      3. May be degraded by sunlight exposure
    2. Menthyl anthranilate
      1. Absorbs shorter wave length Ultraviolet A
    3. Oxybenzone
      1. Absorbs shorter wave length Ultraviolet A
  5. Preparations: Inorganic opaque compounds (scatter light)
    1. Titanium dioxide
    2. Zinc oxide
  6. Efficacy
    1. Reduced with wind, heat, humidity, and altitude
    2. Reduced with poor or inadequate application
      1. Most persons do not apply enough sunscreen
      2. Multiple layers required to reach listed SPF
    3. Reduces Incidence of Actinic Keratoses
      1. Thompson (1993) N Engl J Med 329:1147
      2. Naylor (1995) Arch Dermatol 131:170
    4. Decreases photoaging
  7. Safety
    1. Regular use does not result in Vitamin D Deficiency
  8. References
    1. Potera (1997) Physician and Sports Med 25(5):117-20
    2. (1999) Med Lett Drugs Ther 41(1052):43
    3. Wentzell (1996) Am Fam Physician 53(5):1713

Sunscreening Agents (C0038818)

Definition (MSH)Chemical or physical agents that protect the skin from sunburn and erythema by absorbing or blocking ultraviolet radiation.
Definition (CSP)substance applied to the skin to protect it from the effects of sunlight; sunscreens act by absorbing ultraviolet radiation or by reflecting the incident light.
Definition (NCI)A substance that helps protect the skin from the sun's harmful rays. Sunscreens reflect, absorb, and scatter both ultraviolet A and B radiation to provide protection against both types of radiation. Using lotions, creams, or gels that contain sunscreens can help protect the skin from premature aging and damage that may lead to skin cancer.
ConceptsPharmacologic Substance (T121)
EnglishSunblock, Sunscreen, Sunscreen agent, Sunscreen agents, Sunscreening Agents, Sunscreening preparations, Sunscreens
Spanishpantalla solar, pantallas solares
CreditsDerived from the NIH UMLS (Unified Medical Language System)



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