Sunscreens
Sun avoidance and regular sunscreen use are widely promoted by
organizations and individuals interested in cancer prevention. However,
70% of those who participated in a beach survey were on the beach to get
or to maintain a suntan. Although they stayed on the beach for an
average of 4 hours, only half were using sunscreen.
There appears to be some confusion about the messages people are getting
about sunscreens and why they’re so important. Some use sunscreens to
prevent sunburn, whereas others use sunscreens to improve sun tanning.
Some wish to avoid the wrinkling associated with sun exposure, and
others believe that sunscreens prevent all types of skin cancer, yet
others seem to believe that they can use sunscreens in order to prolong
their time in the sun.
Why Use Sunscreens?
Prevents sun burns
Prevents photodamaged skin (aged look – brown spots, wrinkles)
Prevents actinic keratosis and perhaps squamous cell cancers
May prevent other skin cancers
What Is A Sunburn?
A sunburn is caused by exposing your skin to too much ultraviolet (UV)
light from the sun, that is, lightwaves that measure approximately
200-400nm. UV light can be broken down into 4 component parts that
include:
Ultraviolet A1 (UVA1), 340-400nm
Ultraviolet A2 (UVA2), 320-340nm
Ultraviolet B (UVB), 290-320nm
Ultraviolet C (UVC), 200-290nm
There are two major types of UV sun damage: UVA-type damage, with light
wavelengths of 340-400nm, and UVC-type damage, which includes light
wavelengths of up to 340nm. UVA-type damage can cause the skin to tan
and may cause very weak burns, while UVC-type damage causes skin to
burn.
How Much Sunscreen Should I Apply?
The average user of sunscreen tends to use significantly less sunscreen
than the amount required to achieve the SPF listed on the container.
How Often Should I Apply Sunscreen When I’m Out In The Sun?
Many experts recommend that frequent application during sun exposure is
required. However, a group of children were tested by spreading on one
application of sunscreen to one side of their bodies, and four
applications to the other.
They then spent 6 hours in the sun, one application provided the same
level of protection as four applications, confirming the adequacy of a
single daily application of a sunscreen in that situation.
How Long Before Sun Exposure Should I Apply Sunscreen To My Skin?
As molecules of sunscreen are present in their active state in the
sunscreen, sunscreens work immediately upon application. The only reason
for early application, is to allow absorption into the skin so that the
sunscreen is less likely to be washed off, should the person be entering
the water. Even so, modern sunscreens are quite resistant to removal
from the skin.
Sun Protection Factor (SPF) – What Is It?
SPF is the ratio of the minimal ultraviolet dose required to produce
redness with and without a sunscreen. For example, if it took ½ hour for
your skin to become sunburned without any sunscreen, then for a
sunscreen that has a 15 SPF rating, you could stay in the sun for 15
times longer (or 7.5 hours) before you get sunburned. This is provided,
of course, that you’ve applied the sunscreen properly so that you’re
getting the prescribed protection.
Reactions To Sunscreens:
Sunscreens can be both an irritant and an allergen, though allergic
reactions are rare. Irritant reactions, however, abound. One classic
error in sunscreen application is to put a large amount of sunscreen on
the forehead, perspiration and gravity can cause the sunscreen to
migrate down your forehead into your eyes, causing a stinging sensation.
Some people attribute this to an allergic reaction and discontinue use.
It’s also important to wash your hands after applying sunscreen, since
rubbing your sunscreen covered finger near your eyes can induce an
irritant reaction.
Why Is It Important To Use Sunscreens During Childhood?
It appears that a great deal of time can elapse between actual sun
damage and the development of skin cancer or other skin problems like
photoaging therefore, it is important to protect your skin from an early
age when you are out in the sun.
Sunscreens And The Elderly:
Many elderly people can become quite obsessed by sun avoidance, and
their quality of life can suffer. Sometimes, if they are diagnosed with
an actinic keratosis or basal cell carcinoma, they can become anxious
and almost leap from shadow to shadow. However, few of them are likely
to develop new skin cancers from present sun exposure. As long as they
are prudent about avoiding excessive sun exposure, and protecting their
skin to prevent sunburn, they can continue to enjoy time outdoors.
Can Sunscreens Prevent Cancer?
There is clear evidence that sunscreens are helpful in preventing
actinic keratoses, which are warty lesions that can occur on sun exposed
skin of the face or hands. Research has shown that these lesions can
develop into a cancer called squamous cell carcinoma, and that this is
linked to a cumulative exposure to the sun.
Reference : www.acneguide.ca