Sun Safety: How to Beat the Burn this Holiday

Sunburns

The
main cause of sunburns is not the sun itself but the ultraviolet energy.? Just to complicate matters, there are three
main types of ultraviolet (UV) energy, designated A, B and C.? Erythema is what your skin gets after a day
in the sun, which is redness, some slight swelling and pain.? Doses of UV energy and its effect on the skin
are measured in units called minimal erythema doses (MED).? This MED represents the smallest does of UV
energy to cause that “sunburn” appearance.?

Beachgoers are typically exposed to 15 MEDs of UVB and 4-5 MEDs of
UVA.? Almost all of UVC is absorbed by
the Earth’s atmosphere.? There is
increasing evidence that shows both UVA and UVB can be harmful to human skin
and both can cause skin cancers.?

UVA
rays penetrate the skin more deeply and are largely the cause of aged skin and
wrinkles.? UVB is generally responsible
for most “sunburn” effects and has traditionally been thought of as the cause
of most skin cancers.? Ideally, persons
in the sun should be protecting themselves with a sunscreen that blocks both
UVA and UVB.

Sunscreens

Sun
protection factor (SPF) is the ability of a sunscreen to protect skin from
ultraviolet induced erythemas (sunburn).?
This SPF number is calculated based on the length of time it takes to
cause one MED in protected versus non-protected skin.? Basically, SPF is the amount of time it takes
to causes a sunburn in someone with sunscreen protection versus someone who is
unprotected.? At present, most sunscreens
protect largely against UVB only, although there are some products that are
beginning to protect against both UVA and UVB.??

SPF:???? ??????????? % UVB absorption

2????????????????????????????????? 50.0

4????????????????????????????????? 75.0

8????????????????????????????????? 87.5

15??????????????????????????????? 93.3

30??????????????????????????????? 96.7

50??????????????????????????????? 98.0

Chart
from “A field guide to wilderness medicine” by Paul Auerbach, pg. 69

Clearly,
one can see that UVB protection increases with the higher SPF and use of SPF 30
is becoming more and more advised.

How to Apply Sunscreen

• Apply liberally to all areas of
  exposed skin including backs of hands,? ears, nose and tops of feet

• Apply 15-30 minutes before swimming or
  water exposure

• Reapply immediately after exiting the
  water

• Using sunscreen and DEET based insect
  repellent will reduce the effectiveness of sunscreen by approx. 35%

What is in the sunscreen?

The
ideal sunscreen spread onto your skin easy, does not cause allergy, pimples and
does not stain clothing.? PABA
(para-aminobenzoic acid) is the most common cause of sunscreen dermatitis and
effects 4% of people.? Creams and lotions
spread on the skin well.? Oils spread
very easily but may cause pimples.? For
extreme conditions a wax or ointment will help resist skin chapping.? Aerosols are often wasteful and leave parts
of the skin over coated and others under protected due to difficulty in
ensuring even spray.?

Sun protective clothing

Clothing
that has been tested and proven to block the UV energy is designated by the
term Ultraviolet protection factor (UPF) which is identical to SPF for
sunscreen.?

The tightness of the fabric’s
weave is most important in determining how effective it will be in blocking UV
energy.? A good example of this is Lycra
which can block nearly 100% of UVR when relaxed but only 2% when stretched
tight.? A typical white cotton tshirt has
a UPF of about 5-9.?

Wide brimmed hats
are especially good for protecting the face, head and ears.? Sunglasses should be labeled to protect
against UV energy and side shields do work in decreasing the amount of UV
absorbed by the eyes.

Treating a Sunburn

Sunburns
are largely self-limiting and will typically resolve on their own.? Treatment is largely centered on relieving
symptoms.? Skin moisturizers and cool
compress or cool water baths may help decrease the pain.? There is little evidence to suggest tradition
treatments such as baking soda, aloe and oatmeal are effective pain relief but
there is also a lack of decent studies.?
Oral pain control can be achieved with either aspirin, acetaminophen or
ibuprofen.? After a day in the sun,
dehydration is also a factor and adequate water intake should also be
assured.?

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