+

SUNSCREEN

Laura Bishop, M.D.University of Louisville PediatricsJuly 2013

+UV Light

• UVC• Most damaging• Little makes it

through atmosphere

• UVB• Still damaging• Most common

cause of skin cancer

• UVA• Least damaging• Causes many of

sun’s aging effects

+Sun Avoidance

This is especially important for infants.

Avoid peak sun hourso 10 a.m. to 2 p.m.

Coverageo Select clothing + hats that

cover frequently burned areas o Use sunglasses with UV

protection o Use shade to your benefit

AVOID PEAK

SUNLIGHT HOURSPROTECTI

VE CLOTHING

, SUNGLAS

SES & HATS

SEEK OUT SHADE

SUNSCREEN

+SPF

SPF = sun protection factor against UVB rays UVB rays burn and cause cancer UVA damages skin long-term

SPF is determined by testing 20 sun-sensitive people and measuring the amount of UV rays (in time) it takes to turn skin red without sunscreen. Then it is repeated with sunscreen and the average burn time with sunscreen is divided by the average burn time without sunscreen number.

Calculate how long a sunscreen will protect you: Mins to burn without X SPF number = max

sun exposure time.

+Sunscreen

SPF% UV

absorbed

2 50

4 70

8 87.5

15 93.3

30 96.7

50 98

The previous formula only works if you use the proper amount of sunscreen the average person only uses half as much as

recommended amount.

A higher SPF does not mean an exponential increase in UVB absorption.

FDA has proposed a cap on SPF with anything above 50 reading 50+ to prevent public perception that SPF 80 is significantly more protective.

+Sunscreen: What to Buy

Type of Sunscreen Physical (inorganic)

previously called sunblock, often contains zinc Newer formulations are invisible

Chemical – standard sunscreen

SPFo At least SPF 15 o But not much benefit over SPF 50

Broad Spectrum

Waterproofo DOES NOT EXIST!o Water resistant lasts either 40 or 80 minutes

without reapplication.

+Sunscreen: 2011 FDA Changes

• Should include UVA information: labeled broad spectrum.

• Can no longer be labeled: waterproof, sweatproof or as a sunblock.

• Duration (40 or 80 minutes) of water resistance should be clear.

+Sunscreen: How to apply All types of sunscreen should be

applied 15-30 minutes prior to outdoor activity.

Physical sunscreens are immediately effective.

Throw it away if past expiration date or over two years old.

Apply generously. Experts recommend half a teaspoon

each for the head, neck, and each arm and a teaspoon each for the chest area, the back, and each leg.

Or, a one-ounce shot glass full for an average-sized adult.

Reapply every two hours or per water exposure directions on bottle.

+Don’t miss a spot!

Most commonly missed spots: Creases of elbows and knees Feet Hands (these are exposed to the sun

daily!) Ears and behind ears Scalp and neck

Don’t forget lip protection!

+Resources

http://health.howstuffworks.com/skin-care/beauty/sun-care/spf.htm

http://healthguide.howstuffworks.com/melanoma-and-other-skin-cancers-in-depth5.htm

FDA, “Understanding Sunscreen.” http://www.fda.gov/Drugs/ResourcesForYou/Consumers/BuyingUsingMedicineSafely/UnderstandingOver-the-CounterMedicines/ucm258468.htm

http://www.aap.org/advocacy/releases/summertips.cfm

http://www.healthychildren.org/English/news/Pages/Summer-Safety-Tips-Sun-and-Water-Safety.aspx