Sunburns and Suncreens

What is a tan?

When UV radiation stimulates melanocytes in the germinating skin to generate melanin

Two processes:

immediate pigment darkening

delayed tanning (melanogenesis)

What is sunburn?

Result of an inflammatory reaction

Mediators produce peripheral vasodilation

Superficial burn

mild erythema

tenderness

pain

edema

Superficial/partial thickness burn

blisters form

fever

chills

weakness

shock

200-290 nm

screened out by ozone layer

emitted by some artificial sources of UV radiation

absorbed by the dead cell layer

290-320 nm

sunburn radiation- 90%

responsible for inducing skin cancer, wrinkling the skin, elastosis and collagen damage

responsible for vitamin d3 synthesis

320-400nm

penetrates deeper into the skin

promotes photoaging

suppresses the immune system

founding in tanning booths

What is a drug induced photoallergy?

uncommon immunologic response

Urticaria, bullae, sunburn

reaction is NOT dose related

seen after at least one prior exposure to the agent

What is drug induced phototoxicity?

seen upon 1st exposure to chemical agent

dose related

appears as an exaggerated sunburn

rxn is NOT immunologically mediated

What medications can cause drug induced phototoxicity?

anticancer

anticonvulsants

antidepressants

antihistamines

antihypertensives

anti-infectives

antimalarials

antipsychotics

coal tar

diuretics

NSAIDs

What is premature aging?

wrinkling and yellowing of skin

Elastosis

drying and thickening

cracking, spider vesicles, and growths

Skin cancer

Basal cell carcinoma

-most common

-sunlight causes 95% cases

Squamous cell carcinoma

-2nd most common

-chronic exposure to sunlight

Malignant melanoma

-most fatal

A

asymmetric

B

border irregularity

C

color variance

D

diameter >1/4 inch

E

elevation and enlargement

Risk factors for sun burns

fair skin that always burns

history of more serious burn

blonde or red hair

blue, green, or gray eyes

history of freckling

previous growth on skin

family history of melanoma

current use of an immunosuppressive or photosensitizing medication

Avoidance of sun exposure

complete avoidance of UVR

use of protective clothing

-hat with a 4 in brim

-long pants

-long sleeved shirt

-sunglasses

Sunscreen (SPF15 or higher)

protect against UVB and UVA

-helps reduce risk of skin cancer and premature aging when used in conjunction with limiting time in the sun and wearing protective clothing

<15spf —> sunburn prevention only

SPF 15

filters out 93% of suns UVBs

SPF 30

filters out 97% of the suns UVB rays

AAD recommends using an SPF 30 or higher

SPF 50

filters 98% of suns UVB rays

Aminobenzoic Acid

PABA

Padimate O- wont stain clothes

Sensitizer

Provides lasting protection

AE: contact dermatitis; photosensitivity, stinging

Anthranilates

Meradimate

Usually used in combination with other agents

Weak UV sunscreen

Benzophenones

Dioxybenzone

Oxybenzone

Sulisobenzone

UVA and UVB absorbers

sensitivity reactions

Cinnamates

Cinoxate

Octonoxate

Octocrylene

UVA and UVB absorbers

do not adhere well to the skin

Dibenzoylmethane

Avobenzone- UVA absorption

Commonly included in sunscreen products to increase UVA coverage

Salicylates

Homosalate

Octisalate

Trolamine salicylate

Considered weak sunscreens

Physical sunscreens

scatter UVR

titanium dioxide and zinc oxide

messy, discolor clothing

efficacy is related to thickness they are applied

How do you apply sunscreen?

allow adequate penetration

apply at least 15 mins prior to sun exposure

adult body covered with less than 1 oz

avoid eye contact

external use only

reapply at least every 2 hours

do not use on children <6 months

What to give children >6 months?

use sunscreen that contains zinc oxide or titanium dioxide

keep children in the shade

dress them in long sleeved shirts, pants, wide brimmed hats and sunglasses

How to get relief from sunburns?

avoid further exposure

cool compress

heat stroke occurs with excessive exposure

-analgesics

-protectants

-local anesthetics

fresh aloe vera gel