|
February 18, 2005
News this month
Certain melanin makes skin more vulnerable to sunburn
A Yale therapeutic radiologist may have helped unlock the secret of why blondes
and redheads sunburn more easily.
The type of melanin that causes blonde and red hair actually increases the risk for cell death such as seen in sunburn.
Doctors have long thought that the lack of pigment alone in fair skin makes
a person more susceptible to the damaging effects of ultraviolet sunlight.
But Douglas Brash, PhD, Yale professor of therapeutic radiology, genetics and
dermatology, recently completed a study that suggests the type of pigment an
animal has, in addition to skin transparency, plays a large role in who burns.
Hair color matters most
Dr. Brash found that the type of
melanin that causes blonde and red hair actually increases the risk for cell
death such as seen in sunburn . Blondes and redheads have what is called pheomelanin.
People with darker hair have eumelanin.
Melanin filters out UV radiation, but it also actually increases the UV
harmful effects and causes cell death, particularly when the melanin is the
kind found in light hair or skin. Pheomelanin acts with the sun's UV
rays to increase sun damage.
Blondes, red-heads more at risk
As principal investigator
of the study, Dr. Brash had been curious why people with dark hair and fair
skin weren't as vulnerable to skin cancer as
fair-skinned blondes or redheads. He wondered if their vulnerability was actually
related to the type of melanin.
Brash used laboratory mice engineered with pigmentation for blonde or black
hair, as well as albino mice with no pigment at all. The mice were then exposed
to UV rays about equal to what affects humans.
Melanin is not only good for you, it also can be bad. Douglas Brash, PhD
The cell death in the yellow-haired mice was much more pronounced than
in the dark-haired mice. Cell death was absent in the albinos.
What this tells us is that melanin is not only good for you, it also
can be bad, said Dr. Brash. It depends on the color of your
particular melanin. Even red melanin can vary widely, depending on whether
your ancestors were Irish, Swedish or Dutch, and some of these variations
are known to be associated with greater risk for skin cancer.

Physician Referral Online
A free and confidential service
of Yale-New Haven Hospital.
Physician Referral Online
Using your own criteria, you can request information from a database
of more than 1,000 area physicians who have registered
to participate.
Request an appointment
We would be happy to assist you in scheduling an appointment with
a member of the hospital's medical staff. Use the link above or
call:
203-688-2000
or toll free
1-888-700-6543
to talk with a referral coordinator.

Yale-New Haven was recognized this year by U.S. News & World Report for its cancer services.
|

|

Study confirms what we know: Sun protection is critical
We've always known that people with fair skin and light
hair have a greater chance of getting skin cancer from the sun
than people with darker features. We simply assumed that people
who did not tan lacked the protection that natural pigment provides
in response to sun exposure.
Dr. Brash's study is very important because it explains
in more detail how people with fair skin and light hair are at
greater risk for skin cancer.
Type of melanin is a co-conspirator in causing skin
cancer
Now we understand that it's
the type
of melanin that
blondes
and red-heads
havepheomelaninthat
seems to be important in skin cancer risk. This type of melanin
acts as a co-conspirator in causing a
person to be more at-risk
for developing skin cancer. People with the other type of melanineumelaninhave
darker hair. Interestingly, while dark-haired people with eumelanin
can be fair-skinned, they don't burn as readily as a blonde
or a red-head.
People fall into skin types. People with Type I skin burn in
the sun and never tan. Type II individuals burn first then tan.
Type III people always tan. At the far end of the spectrum are
people who are very darkly pigmented. People with Type I skin,
those at greatest risk for skin cancer, have pheomelanin.
Vigilance about sun protection
This study gives
us more reason then ever to be vigilant about taking care of
our skin and using good sun protection. If you didn't believe
it before, the results of this study speak for themselves.
There’s no such thing as a healthy suntan.
For sun protection, I recommend using a sunscreen with a sun protection
factor (SPF) of 30 and reapplying it every couple of hours while active outdoors.
Be sure the product you use has protection for both UVA and UVB rays:
- Look for sunscreens with parsol 1789 (avobenzone), the only
FDA-approved UVA blocker.
- Products with titanium dioxide or zinc oxide provide protection
against both UVA and UVB rays.
- Coppertone has just introduced a new sunscreen in a continuous
spray which allows reaching difficult locations and provides
even coverage of the whole body.
- Look for other innovative products that will make it easier
to apply sunscreen regularly.
Protect yourself from the sun
Other sun protection
measures to take include:
- Wear a wide-brimmed hat
- Stay out of the sun during the peak hours of 10 a.m. - 4 p.m.
- Wear sunglasses that provide UVA protection. UVA exposure
can cause cataracts.
- Wear sun-protective clothing if you are particularly fair.
There's no such thing as a healthy suntan. A tan is the
body's reaction to sun exposure. We already know that just
one blistering sunburn as a child can increase a person's
lifetime chances of getting melanomathe most serious form
of skin cancer.
The rays that come from the artificial bulbs [in tanning parlors] are just as likely to cause skin cancer as natural rays from the sun.
Tanning salons
No discussion on sun protection would
be complete without discussing the bad effects of tanning salons. We have
seen a high increase of young people coming in with skin cancer, which we
attribute to the popularity of tanning parlors. The rays that come from
the artificial bulbs are just as likely to cause skin cancer as natural
rays from the sun.
Have an annual body screening
As a last word
of advice, see your doctor once a year for a full body skin cancer
screening, especially as you age. Your doctor can find lesions
of concern that you might not be able to see yourself.
Dr. Leffell is an attending physician at Yale-New Haven Hospital,
professor of dermatology and surgery and chief of the section of dermatologic
surgery and cutaneous oncology at the Yale School of Medicine. He is also
author of Total Skin: The Definitive Guide To Whole Skin Care For Life (Hyperion,
2000).
|