sun induced skin disorders

ultraviolet a

• Longest wavelength

• Can penetrate dermis

• Penetrates car windows

ultraviolet b

• Shorter wavelength

• Can penetrate epidermis

• Blocked by car windows

ultraviolet c

• Shortest wavelength

• Does not penetrate ozone layer

• Is not a main cause of photodamage

uva effects

⚬ Photoaging effects

⚬ Inflammation

⚬ Skin cancers

uvb effects

⚬ Sunburn

⚬ Erythema (redness)

⚬ Vitamin D3 synthesis

⚬ Some photoaging effects

categories of sun induced skin disorders

• sunburn and suntan

• photoallergy

• phototoxicity

• skin cancer

• premature aging

what are the most common sun induced skin disorder

sunburns and suntans

sunburn

Acute reaction to excessive UVR exposure, resulting in inflammation of exposed skin

Maximum response at 6 hours and fades within ~2-3 days

Can form vesciles or bullae

Advise patients with fever, chills, weakness, and CNS dysfunction to contact their doctor

suntan

Result of melanocyte stimulation from UVR exposure

2 Suntan Phases:

1) Immediate suntan: caused by oxidation and redistribution of existing melanin

2) Delayed suntan: caused by the increased generation of melanin; occurs ~3 days after exposure and lasts 10-30 days

Suntans are ______, while sunburns are ______

protective; damaging

Exogenous substance photodermatoses:

chemicals, medicines, and other outside substances causing increased, chemically induced reactivity of the skin to UVR and/or visible light

photoallergy

• Reaction that triggers an antigenic (allergic) reaction in the skin

• Occurs after 1 or more exposures

• Not dose/amount related

• Cross-reactivity is common

• Pruritis with eczematous lesions

  
  

phototoxicity

• Reaction that is NOT immune mediated and causes direct tissue injury

• Occurs with/after the first exposure

• Dose/amount related

• Cross-reactivity rarely occurs

• Pruritis, redness, and edema

goals

short term

• Avoid or minimize sunburns, photosensitivity reactions, and photodermatoses

long term

• Prevent skin cancer and avoid premature aging of the skin

physical characteristics that increase risk of sun induced skin disorders

• fair complexion

• skin that burns easily and never tans

• history of 1 or more peeling burns

• blonde or red hair

• blue or green eyes

• freckling tendency

• atypical or large number or nevi (moles)

• previous sun induced skin growth

medical history that increase risk of sun induced skin disorders

• Skin cancer history

• Family history of melanoma

• immunosuppression from disease states or medications

• current use of photosensitizing medication or substance

• hereditary conditions predisposing individuals to sun induced skin disorders

non patient specific risk factors

• time 9 am - 3 pm

• latitude: closer to equator

• ozone: thinner ozone

• altitude: higher altitude

• surface reflectivity: glass, sand, snow, and water

• season: spring and summer

• cloud cover: thinner and or sparser clouds

• uv index: scale of 1-11+

how is spf measured

• Calculated using the minimal erythema dose (MED)

• NOT calculated by: length of exposure or degree of redness

degrees of spf

SPF 15 = 93% UVB blocked

SPF 30 = 97% UVB blocked

SPF 50 = 98% UVB blocked

SPF 15+ for all

SPF 30+ for those at higher risk

SPF 15+ reduces risk for:

• skin cancer

• photodermatoses

• sunburns/suntans

chemical (organic) sunscreen

Absorb and block UVR transmission to epidermis

physical (inorganic/mineral) sunscreen

Create a barrier to reflect and scatter UVR

• Zinc oxide - UVA/B

• Titanium dioxide - UVA/B

sunscreen alternatives

• wide brimmed hat

• pants and long sleeve shirt

• dry, dark colors, tightly woven fabrics

• specific sun protective clothing

• uv blocking sunglasses

• sun avoidance

sunscreen directions

Re-apply:

Every 2 hours

Every 40-80 minutes if in water or sweating Immediately after towel drying

1 ounce of sunscreen

apply 15 minutes before uvr exposure

counseling points special populations

Infants less than 6 months old:

• Keep out of sunlight or use sun-protective clothing

⚬ Increased risk from sunscreen adverse effects

• If the parent wants to use sunscreen, refer to a provider

Breastfeeding:

• Oxybenzone has been found in breast milk in studies

⚬ No official recommendations

⚬ Stick to physical sunscreens