UV Light

bands of UV light

UVA

UVB

UVC

UVA

long wave

315-400 nm

UVB

middle wave

280-315 nm

UVC

short wave

200-280 nm

general effects of UV light

erythema

tanning

vasodilation

epidermal hyperplasia

vitamin D synthesis

bactericidal effects

UV light during the course of treatment

progressively higher dose of UV light needed

vasodilation

UV induces inflammatory reaction, stimulates repair of cutaneous epithelium, enhances granulation tissue formation, increases BF to area

occurs several hours after treatment

vitamin D production

increases calcium and phosphorus absorption in GI tract

proper absorption needed for cellular repair

bactericidal effects

primarily caused by UVC

damaging DNA of bacteria

possible RNA effects

toxic substance production

UVB effects

erythema

blistering

epidermal hyperplasia

more carcinogenic

UVC effects

bactericidal

viricidal

UVA penetrates through

several mm of skin

UVB and UVC are absorbed in

superficial epidermis

UVB hot quartz

inflammatory reaction in chronic wounds, stimulate granulation tissue (healthy) growth, breakdown and elimination of necrotic tissue (dead)

UVC cold quartz

for infected wounds

MED

minimal erythemal dose

MED test

expose patches of skin for different amounts of time and compare skin pigmentation within 1-6 hours

don’t need to do MED test for

UVC

to treat wound with UVC

it takes 4 seconds to kill group A strep (120 sec)

takes 90 sec to kill methicillin-resistant or antibiotic-resistant

takes 45 sec to kill vancomycin-resistant or antibiotic-susceptible E. faecalis

takes 30 sec to kill highly colonized or infected with antibiotic-susceptible bacteria

treat with UVC for

30 seconds, 10-12x per day

takes how long for germs to migrate to top of wound?

2 hours

UVC does not

harm wound matrix, would have to be on for many minutes

clinical indications of UV light

psoriasis

scleroderma, eczema, atopic dermatitis

wound healing

treatment prep

debride any necrotic tissue

irrigate wound with saline, pat dry with sterile towel

apply spf 30 blocking agent to periwound skin or use petroleum and place paper towel over top (UVB)

goggles worn by pt and PT

light source distance from wound

1 inch

UV light contraindications

TB, cardiac, hepatic insufficiency

renal disease

systemic lupus erythmatosus

CA in wound/periwound tissues

fever

acute-onset psoriasis

herpes simplex

hyperthyroidism

severe diabetes

UV light precautions

recent x-ray therapy

photosensitivity

very fragile skin

photosensitive medications

no dose of UV should be repeated until the effects of the previous dose have disappeared

UV light adverse effects

burning (UVA, UVB)

premature aging of skin

eye-damage (use goggles)