Sun and Skin

    Intro

    • UVB - Burning, sunburn, delayed tanning, aging and skin cancer
    • UVA - Aging, penetrates deeper, not as intense, penetrates through window glass, immediate and persistent pigment darkening, skin cancers
    • Melanoma >68,000 cases/year
    • 1/7 risk of skin cancer
    • 1/62 risk of melanoma

     

    Sun Protection

    • SPF = Sun Protection Factor = TimeToBurnWithSunscreen / TimeToBurnWithoutSunscreen
    • SPF15 cover 93% of UV
    • Apply 15-30min before exposure, apply liberally
    • Kids
      • Keep out of sun 10-4pm
      • Hats, tightly woven clothing
      • Sunscreens >6mo
      • Careful of water, sand, snow, concrete (reflects UV)
    • Clouds: allow up to 80% of UVB

    Melasma

    • Strict sun avoidanceMelasma.png
    • Bleaching creamsHydroquinone
      • Lustra
      • Ultraquin
      • Neostrata HQ
    • Stop OCP

    Actinic Keratosis

    • Most common pre-malignant skin lesion
      • Arises from cumulative effect of UV exposure
      • 5-20% of pts develop malignancy
      • 0.25-1% of AK convert to SCC/year
      • 60% of new SCC in site of previous AK
    • Well-circumscribed erythematous base with adherent scale (tacked-on appearance)...often easier to feel than see.
    • Flesh colored or pigmented.
    • Usually multiple
    • Superficial - little or no invasion

    ActinicKeratosis.pngActinicKeratosis2.png

     

     

    Non-Melanoma Skin Cancer

    Risk Factors

    • External: UV, radiation, immunosuppression
      • Immunosuppression is huge: 50% develop skin cancer in 20yrs post-transplant, 1 in 4 heart transplant patients die of skin cancer in Australia.
    • Genodermatoses
      • Albinism
      • Xeroderma pigmentosum
      • "Nevoid BCC Gorlin Syndrome"
    • SCC precursor lesions (AK, SCC in situ)
    • Chronic Skin Disorders (SCC only)
      • HPV
      • Burns, Scars, Ulcers

    Treatment

    • Topical (limited efficacy) - 5-FU, Imiquimod
    • Destructive (no histologic margin confirmation)
      • Scraping --> Curettage
      • Burning --> Electrosugery, laser
      • Freezing --> Cryotherapy
      • Photochemical --> Photodynamic therapy
      • Irradiating --> Rads
    • Sugery
      • Standard excision
      • Mohs micrographic excision (taking slices and looking under microscope until margins clear) - minimally invasive, cosmeticaly pleasing.

     

    Basal Cell Carcinoma

    • 11-33% lifetime risk, usually >40yo, 86% occur on H&N, usually nose
    • Types:
      • Noduloulcerative (50%-54%)
      • Superficial (9-11%)
      • Pigmented (6%)
      • Morpheaform (2%)
      • Basosquamous (1%)
    • Almost never metastasis

    Noduloulcerative BCC

    • Most common
    • Single
    • Nodular, smooth, pearly well defined border, telangiectasia, can ulcerate & crust
    • Hx: pimple-like lesion that bleeds and does not heal.

    BCCNoduloulcerative.pngBCCNoduloulcerative2.png

     

    Superficial Multicentric BCC

    • Often with actinic damage
    • Usually on trunk
    • Lightly pigmented, erythematous & patch like
    • Eczema & psoriasis

    BCCSuperficial1.pngBCCSuperficial2.png

     

     

    Morpheaform / Sclerosing BCC

    • Indurated yellow-white sclerotic plaque w/ ill defined borders
    • Often difficult to see, palpation reveals indurated mass

    BCCMorpheaform.pngBCCMorpheaform2.png

     

     

    Pigmented BCC

    • Clinical features & behavour similar to noduloulcerative
    • Brown pigmentation with rolled pearly borders - often mistaken for melanoma

    Squamous Cell Carcinoma

    Bowen's Disease: Intraepithelial SCC

    • Aka carcinoma in-situ
    • Older pts, solitary, sun & non-sun exposed areas
    • Well demarcated, irregular borders, erythematous & scaly plaque
    • May be pruritic, crust & bleed
    • 3-5% become SCC
    • Tx:
      • Adequate excision
      • Topical therapy if multiple lesions

    Squamous Cell Carcinoma

    • Two types:
    1. Actinically induced SCC
    • more cmmon
    • Solar etiology - occur in sun exposed areas & areas of actinic damage
    • low incidence of metastatsis (<1%)
    1. De novo SCC
    • Associated with non-solar etiology
    • Higher metastatic rate (~10-30%)
    • Presentation
    • Usual Presentation: Thick & Scaly hyperkeratotic plaque, ulcerated base when crust removed.
    • Other Presentations: Persistent ulcer, pigmented

     

    Melanoma

    Risk Factors

    • Light Complexion - hair, eyes, skin
    • Lots of nevi (moles)
    • Dysplastic nevi
    • Congenital nevi
    • Family hx of melanoma
    • Excessive sun exposure

    Dysplastic nevi

    • Irregular "hazy" margin
    • Asymmetric
    • Irregular colour, very dark, or mixed in color
    • Usually >6mm

    DysplasticNevi.png

     

    Types of Nevi

     

    Junctional Nevi

    JunctionalNevus.png

     

    Compound Nevi

     

    CompoundNevus.png

     

    Intradermal Nevi

     

    IntradermalNevus.png

     

    Blue Nevus

     

    BlueNevus.png

     

    Halo Nevus

     

    HaloNevi.png

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