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What is UV used for?
chemical effects on skin, not thermal
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How deep does UV penetrate skin?
2mm or less
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How much UV rays come from the sun?
7%
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What are 2 types of artificial sources of UV?
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What are some physiological effects?
- latent erythemia
- hyperplasia (thickening of epidermis)
- pigmentation change
- destruction of bacteria
- formation of vit d
- increased resistance to infection
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What are some effects of excessive dosage?
- burns
- symptoms of protein shock, pallor, shallow pulse, low BP
- photosensitivity with drugs-HTN, gold, quinine
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Which erythemal reaction has no effect?
suberythemal dose (SED)
- irridation insufficient to cause reddening
- usefule in photosensitization with UV
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What type of erythemal reaction do we want to achieve?
minimal erythemal dose (MED)
- slight reddening with peeling (appears within 8 hours, disappears withing 24 hours)
- used for intial dosage of UV
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What type of erythemal reaction has reddening that appears after a few hours (6ish) and lasts 1-3 days?
first degree erythemal dose (1ED)
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What type of erythemal reaction is marked by reddening with considerable itching that subsides in 3 days (sunburn like)?
second degree erythemal dose (2ED)
appears in 2 hours, edema, peeling, pigmentation
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What type of erythemal reaction produces severe reddening after 2hours and lasts several days; consists of blistering, peeling, and deep pigmentation?
third degree erythemal dose (3ED)
nasty burn
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How do you perform a MED test?
- apply strip (6holes) to an area not exposed to sunlight
- set lamp 30inches away from surface, and perpendicular
- expose first hole for 30 sec, then second for 30 sec..expose the last 4 holes 15 seconds each (total 120 seconds)
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After giving a MED test, what should be done?
- pt must check test area every 2 hours and report what each hole is doing
- shortest dose to appear and disappear withing 24 hours is the MED
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What are some indications?
- acne
- psoriasis
- decubitus ulcer??
- general debility (try to make them hungry or something, get some sort of reaction)
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What are some contradictions?
- tb
- cardiac/kidney diseases
- hyperthyroidism
- dm
- over the eyes
- if getting xray txs or have within 3 months
- very sensitive skin
- if they have SLE (lupus)-very high sensitivity to light
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What are some special precautions?
- both you and pt must wear goggles
- your sking will also be exposed and treated
- CAREFULLY monitor times
- treat burns if they occur
- blondes/red heads/skin thin/old/young
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