Sun and Skin Disorder Flashcards
How is the protective effect on the skin obtained by sun exposure
UVR stimulates melanocytes to generate melanin
UVR oxidizes melanin in the epidermis
Sunburn mediators
histamine, lysosomal enzymes, kinins, prostaglandins
-> cause vasodilation, more blood flow (redness), inflammation, lymphocytic infiltration
Signs of severe Sunburn
Severe: blistering, fever, N/V, delirium, shock -> REFER
Mild: Scaling, exfoliation
Managing Superficial Burns
-Cool tap water for 10-30 minutes (cooling delays the progression of burn)
-Aspirin, NSAIDs, Acetaminophen
-skin protectants and soothing agents
-physical protection -> dressing
Deeper burns with blister
Leave blisters -> can cause scars
-use coverings: prevents contamination, creates protection and barrier for the filled sack
-Anesthetics like Benzocaine, Dibucaine, or Lidocaine up to 20%
-Antihistamine in case of itching
-if BSA > 2% refer - but leave it up to the patient, depends on how they feel
Risk of skin cancer
- Fair skin
- Large # of nevi (moles)
- Large moles
- Family Hx
- Severe sunburns as a child
- Excessive sun exposure or visits to a tanning salon
Basal Cell Carcinoma
aggressive, invasive, rarely metastasize
Translucent, smooth surface
face, nose
Squamous cell carcinoma
-Grows very slowly
-found in keratinocytes in the epithelial layer
-Isolated plaque on a sun-exposed area
Melanoma
can be from natural skin, 30% from nevi
grows horizontally, then vertically
ABCD: asymmetric shape, border irregular, color variation, diameter > 6 mm
Melanoma
-can be from natural skin, 30% from nevi
-grows horizontally, then vertically
-ABCD: asymmetric shape, border irregular, color variation, diameter > 6 mm
-looks like moles
-fairly easy to spot, but has most complications
SPF - Sun protection factor
in vitro experiment
observe the minutes it takes to cause redness of the skin
repeat the experiment with sun protection and divide it by 2
sunscreen with higher numbers protects longer
-MED protected skin / MED unprotected
skin
-for people with pale skin 30 is reasonable
-usually 97& of UVR is blocked -> 3% reaches the skin
-with SPF 50 will block 98%
Difference between water resistance and very water resistant
water-resistance: 40 min protection before need to reapply
and very water-resistance: 80 min protection
if in the water (surfing, swimming) more applications are required
MOA for sunscreens
-chemical sunscreens: Absorbs UVR
-physical sunscreens: Reflect/scatter UVR (opacity)
Dosing and administration
-FDA: 9x ½ tsp portions to cover the body
-protect lips
-Apply early (15-30 mins prior) and on affected exposed areas
Fades
Dihydroxyacetone: binds with amino acids in stratum corneum fades in 5-7, no sun protection
B-carotene, and canthaxanthin – dyes, bind to sub-Q fat, splotches, discolor feces
