Certain melanin makes skin more vulnerable to sunburn (1 of 2)

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.”

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).