SKINIPEDIA - Skin Articles: Skin and Touching and Feeling

Tom Stevens sits across from me at a cafe in a small town in upstate New York. He has a handsome face and a powerful build. But his ears are stubs tucked tightly to the sides of his head, and when he takes off his baseball cap, I see that his scalp, except for a thin strip, is a mass of scar tissue.

"I lost my helmet somewhere in the house trailer just before the flashover hit," says Stevens. "It was about 2,000 degrees Fahrenheit (1,093 degree Celsius) in there when I jumped out the window."

Five years ago Stevens was a volunteer firefighter. Now, preparing for his sixth major reconstructive surgery, he laughs. "I'm learning more about skin than I ever wanted to know."

If you took off your skin and laid it flat, it would cover an area of about 21 square feet (2 square meters), making it by far the body's largest organ. Draped in place over our bodies, skin forms the barrier between what's inside us and what's outside. It protects us from a multitude of external forces. It serves as an avenue to our most intimate physical and psychological selves.

"I've had 'em burned off, cut off, x-rayed, you name it," says former Australian lifeguard Don Bennewith of his skin cancers. Each adhesive dot represents a removed lesion. "I lost count at 532," he says. With only minutes of sun exposure, skin cells stained with a fluorescent dye show signs of increasing DNA damage. The cells may repair such damage, but sometimes they fail and become cancerous.

This impervious yet permeable barrier, less than a millimeter thick in places, is composed of three layers. The outermost layer is the bloodless epidermis. The dermis includes collagen, elastin, and nerve endings. The innermost layer, subcutaneous fat, contains tissue that acts as an energy source, cushion, and insulator for the body.

From these familiar characteristics of skin emerge the profound mysteries of touch, arguably our most essential source of sensory stimulation. We can live without seeing or hearing—in fact, without any of our other senses. But babies born without effective nerve connections between skin and brain can fail to thrive and may even die.

Laboratory experiments decades ago, now considered unethical and inhumane, kept baby monkeys from being touched by their mothers. It made no difference that the babies could see, hear, and smell their mothers; without touching, the babies became apathetic and failed to progress. Deprived of their mothers, they did not explore as young primates normally do; rather they "threw themselves prone on the chamber floor, crying and grimacing all the time, or huddled against a chamber wall, rocking back and forth with their hands over their heads or faces," according to one report.

For humans insufficient touching in early years can have lifelong results. "In touching cultures, adult aggression is low, whereas in cultures where touch is limited, adult aggression is high," writes Tiffany Field, director of the Touch Research Institutes at the University of Miami School of Medicine. Studies of a variety of cultures show a correspondence between high rates of physical affection in childhood and low rates of adult physical violence.

While the effects of touching are easy to understand, the mechanics of it are less so. "Your skin has millions of nerve cells of various shapes at different depths; explains Stanley Bolanowski, a neuroscientist and associate director of the Institute for Sensory Research at Syracuse University. "When the nerve cells are stimulated, physical energy is transformed into energy used by the nervous system and passed from the skin to the spinal cord and brain. It's called transduction, and no one knows exactly how it takes place." Suffice it to say that the process involves the intricate, split-second operation of a complex system of signals between neurons in the skin and brain.

This is starting to sound very confusing until Bolanowski says: "In simple terms people perceive three basic things via skin: pressure, temperature, and pain."

And then I'm sure he's wrong.

"When I get wet, my skin feels wet," I protest.

"Close your eyes and lean back," says Bolanowski.

Something cold and wet is on my forehead—so wet, in fact, that I wait for water to start dripping down my cheeks. "Open your eyes," Bolanowski says, showing me that the sensation comes from a chilled, but dry, metal cylinder. The combination of pressure and cold, he explains, is what makes my skin perceive wetness.

He gives me a surgical glove to put on and has me put a finger in a glass of cold water. My finger feels wet, even though it's not touching water. My skin, which seemed so reliable, has been deceiving me my entire life. When I shower or wash my hands, I now realize, my skin feels pressure and temperature—it's my brain that says I feel wet.

Perceptions of pressure, temperature, and pain manifest themselves in many different ways. Gentle stimulation of pressure receptors can result in ticklishness, gentle stimulation of pain receptors in itching. Both sensations arise from a neurological transmission, not from something that physically exists.

Scratching puts a quick end to a variety of itches by creating a counter-irritation on the skin that diverts the brain's perception of the itch. Although no one has identified exactly what part of the brain receives itch signals, itches trigger activity in areas of the brain that prompt arm movement, presumably initiating a scratch response.

But there is more to relieving some itches than a simple scratch. "Few medical researchers pay serious attention to itches even though everyone experiences them," says Goh Chee Leok, clinical professor of dermatology at the National Skin Centre in Singapore. "There are pain clinics but no itch clinics."

Last year Leok and colleagues from all over the world gathered in Singapore for the first international itch meeting. Findings reported at the meeting revealed some curious patterns. Temperature, for example, can inhibit an itch. Also, if a finger on one hand itches and you put the same finger on the other hand in cold water, the itch on the first finger goes away. Imposing pain in one place can inhibit an itch in another place.

"Can you imagine an itch that never goes away no matter what you do?" The question comes from a young woman with psoriasis. Her knees are covered with red blotches, scaly and peeling.

Skin cells migrate from their birthplace at the base of the epidermis outward to the surface of the skin. This movement, in normal skin, takes about a month. In people suffering from psoriasis—thought to be an immune-related disease, in which the body's defenses against infection attack the body's own tissues—the shedding is accelerated, sometimes to as few as four days. As a result the skin may become a less effective barrier.

Other causes of persistent and at times incessant itching include kidney disease, stroke, brain tumor, liver disease, Hodgkin's disease, and other malignancies of the lymphatic system. Finding relief for patients plagued by this kind of itching presents a major challenge to the medical community.

Skin, I'm realizing, is under constant assault, both from within the body and from forces outside. Repairs occur with varying success.

Take the spot where I nicked myself with a knife while slicing fruit. I have a crusty scab surrounded by pink tissue about a quarter inch (0.64 centimeters) long on my right palm.

Under the scab, epidermal cells are migrating into the wound to close it up. When the process is complete, the scab will fall off to reveal new epidermis. It's only been a few days, but my little self-repair is almost complete.

Likewise, we recover quickly from slight burns. Touch a hot burner? Put your finger in cold water. Chances are you will have no blister, little pain, and no scar.

Severe burns, as Tom Stevens and others like him can attest, are a different matter. Stevens suffered some second-degree burns that destroyed epidermis and parts of the dermis, as well as extensive third-degree burns in which all the skin was destroyed. His burns have forced him to establish a whole new relationship with his skin.

"My hands are bothering me today," he says during one of my winter visits to his home in New York. "I have trouble keeping them warm on cold days like this." Stevens's hands get cold because the skin on them is mostly gone, replaced by scar tissue. He also has trouble in hot weather. Healthy skin has about 650 sweat glands per square inch (6.5 square centimeters), but Stevens's hands can't sweat. "I don't think most people realize how much heat they release through their hands," he says. Stevens must also battle itching and numbness. "If I rub on moisturizing lotions it helps. It feels like blood returning to a limb after it's fallen asleep," he says.

Sometimes the most difficult areas for burn victims are areas that were not burned at all. To cover areas exposed by severe burns until scar tissue can grow, surgeons often "harvest" skin from healthy areas, causing the equivalent of new second-degree burns.

If patients are too seriously burned to endure this additional damage, surgeons attempt skin grafts from other sources. Success with cadaver skin is limited, because in most cases the patient will shortly reject it. Immunosuppressants, which normally aid in preventing rejection of transplants, are of little value because burn patients are at such high risk for infection that it's not safe to suppress their immune systems in any way.

Pigskin, which resembles human skin more closely than that of any other animal, was once used as a temporary bandage to protect the burn as it healed. Since the 1970s doctors have been working to develop other materials that mimic the structure of the dermis. Some are made from cow collagen and shark cartilage, and scientists are also working with silicone. Applying such material to burned areas encourages damaged dermis to create new collagen of its own. Other advances include the use of small samples of the patient's own normal skin to grow larger sheets of new skin on an artificial dermis. This skin is then grafted onto the patient.

Two months after the attacks on the World Trade Center and the Pentagon left behind many serious burn victims, I visited the physical therapy room at the Burn Center of the Washington Hospital Center in Washington, D.C. "If you see us laughing or joking, don't take it wrong," a handmade placard read. "We're trying to relieve the stress."

James Jeng, associate director of the center, explained that the first thing surgeons do after a burn patient enters the hospital is cut away the burned tissue with scalpels. "What we do now is terribly bloody and barbaric," says Jeng, who is working to devise a way to use computer-directed lasers to achieve this first step with more precision and less damage.

"But the greatest damage from burns often occurs in the days after the patient arrives at the hospital," Jeng explains. "Blood flow to surrounding skin is reduced, which converts living, unharmed tissue to dead tissue, dramatically increasing the severity of the injury." The process can continue for one to two days after the burn.

Jeng, who has been operating on burn and other trauma patients for nearly a decade, believes that the next major breakthroughs in burn treatment will include not only better artificial skin but also the prevention of this conversion process.

That burned skin can hurt healthy skin is news to me. "But think about when we were hunter-gatherers," says Jeng. "Humans could survive and go on with an injury that was not too bad, but they would die if their injuries made them so slow and weak that they'd endanger the entire group. Once you're burned past a certain point, nature may intend for you to die."

Less immediately but just as dramatically damaging to skin are burns caused by the ultraviolet radiation in sunlight.

Epidemiological evidence as far back as the late 19th century suggested a link between sun exposure and deaths from cancer, but few experts noticed. In the 1940s Sigismund Peller of the Johns Hopkins School of Hygiene theorized that exposure to sunlight during childhood and adolescence, though it may result in cancer of the skin or lips, helps to prevent the development of deadly cancers in other parts of the body less accessible for treatment.

While sunlight is necessary for the human body to be able to produce vitamin D, repeated sunburn and prolonged exposure to ultraviolet radiation from sunlight can cause irreparable damage to the DNA within skin cells and suppress the immune system, allowing cancerous cells to take root. Cases of melanoma, the most serious form of skin cancer, have nearly doubled in the United States in the past two decades, making this one of the most rapidly increasing forms of cancer. More than 50,000 new cases are reported to the American Cancer Society each year. It's likely that many more go unreported.

The health of our skin and its ability to perform its protective functions are crucial to our well being, but the appearance of our skin is equally—if not more—important to a vast number of people on this planet. And what's appealing is a matter of considerable subjectivity.

Take skin color. The color of skin depends mainly on melanin, a brownish pigment produced by melanocytes in the epidermis. All people have about the same number of melanocytes; it is the amount of melanin they produce that varies among lighter and darker skinned people.

Heredity is a primary determinant of how much melanin the melanocytes produce in any given person. But for centuries humans have taken measures to alter what heredity determines, and attempts to either lighten or darken skin color have long been part of various beauty regimens.

In the 1800s many people of European descent deemed white skin desirable—it meant that its owner was a member of the upper class and did not have to work in the sun. Women even ate arsenic, risking illness and death, to make their skin pale. Among dark-skinned people in some parts of the world, skin whiteners and lighteners are still popular. A label on a product manufactured in Paris (which I purchased in Bangkok) claims to be "the first technology which regulates the different steps in the skin pigmentation process, to perfect the whitening efficiency." Those who cannot afford such products—or who want faster and more dramatic results—sometimes use illegally imported creams containing steroids or concoct their own abrasives.

Friends of mine in Indonesia have a daughter who just turned 16. As a coming-of-age gift her classmates gave her a skin whitening kit and a package of other whitening products, all designed for "the teenage skin." To be "fair," her friends told her, is to be desirable.

In other cultures during the 20th century, as cities grew and work moved indoors, perceptions about paleness shifted in the opposite direction. Tanned skin began to denote leisure time, and fashion trendsetter Coco Chanel announced in 1929 that a "girl must be tanned."

By June 2000, with increased health warnings and rising melanoma rates, an article published in Women's Wear Daily insisted on the use of sunscreen because "It will be a cold day in hell before there's a shortage of bodies sun tanning on the beach, and this summer, a sun-roasted hide is more fashionable than ever."

To look tan might be a fashion necessity, but to look young is just as desirable in many circles (even though the tanning process accelerates the aging of the skin). The fight against aging skin appears, when I look around the magazine stands in the supermarket, to have taken on the proportions of a war.

As we age, the skin loses its ability to retain moisture; the dermis loses its elasticity and its collagen stretches; and lines and wrinkles from laughter and other habitual facial expressions deepen.

To counter these effects, consumers worldwide spend several billion dollars a year on skin care products, not including cosmetics or services like facials. Most is spent by women, but marketers now target men, as well as girls as young as eight, encouraging them to try to prevent or diminish signs of aging. "Skin products can give everyone more confidence," one company executive explains.

My wife smiles when I start to bring home magazines filled with suggestions for various products and regimens: "Get Your Best Skin" and "Your Ideal Skin. See it. Feel it. Have it." I soon realize the cause for her amusement. They all basically say the same thing and have for years. To fight wrinkles, hydrate your skin. Wash well but not with harsh cleansers. Use absorbable antioxidants, such as vitamins A, C, and E, which may counteract free-radical damage caused by the sun and natural aging. Toxins in cigarette smoke accelerate skin-cell aging.

But many people want more extensive results than such sensible measures afford. Americans now spend over 300 million dollars annually on the injection of botulinum toxin—produced during World War II by the U.S. biological weapons program—that temporarily paralyzes facial muscles to stop habitual movements, such as frowning, that contribute to lines and wrinkles. An estimated 1.6 million botulinum toxin (known as Botox) treatments were administered in the U.S. in 2001.

With such treatments, it seems to me, your face becomes less the story of your life and more the measure of your vanity and bank account, a step toward Aldous Huxley's Brave New World, in which faces remain “youthful and taut-skinned" throughout old age. When I telephone a prominent dermatologist to discuss skin diseases, the recording I hear while I wait on hold says: "Are you frustrated by crow's-feet and old wrinkle lines? Do you look at old photos? Please schedule a consultation."

Enough. I decide to experiment. Every day I'll treat the left half of my face with antiaging skin care products. The right side will receive nothing. I'll see if anyone notices a difference.

I choose Sisley, a pioneer in botanical products, and meet with representatives at the company laboratories just outside Paris. "Give it a month, and you'll see a difference in the half of your face that you treat," says one researcher. Company officials nod, their confidence built on studies documenting the effects on skin of oils and extracts from sage, cornflower, lily, horsetail, and apple seeds. They show me magnified before-and-after images in which ranges of wrinkles have been reduced to foothills.

After a month I abandon the experiment, although the treated half of my face looks marginally better (at least to me—no one else notices). I'd hoped for something more amazing. Besides, smearing three creams on my face twice a day takes a lot of time, and the creams feel cold.

I decide that although it's all right for me to try to look better, my wrinkles are not something to be cured. Wisdom, character, and experience should show on a face. I begin to see sense in the words of New York photographer Chester Higgins, whose images document the beauty in older faces. Higgins sometimes walks up to women and offers a compliment: "I love your crow's-feet."

My complacency disappears when I pick up The Wrinkle Cure and The Perricone Prescription, both by Nicholas Perricone, a dermatologist and professor of medicine at Michigan State University's College of Human Medicine. I do another about-face. Perricone argues that you can make your skin more healthy and keep it from aging by changing diet, taking the right supplements and vitamins, increasing exercise, and drinking lots of water.

Perricone's recommendations coincide with guidelines for preventing heart disease and cancer. Maybe vanity can be an avenue to good health.

My interview with Perricone takes place at the St. Regis Hotel in New York City. As we sit down together I ask him what stimulated his interest in skin. He shows me the discolored lines in his hands, evidence of the eczema that has plagued him since his teens.

Afternoon tea arrives, complete with multi-tiered plates of sandwiches and cookies filled with the carbohydrates and sugars Perricone advises people not to eat because they raise blood sugar levels, triggering, he says, inflammation that contributes to problems ranging from heart disease to wrinkling. For three hours we converse over this food, which neither of us touches.

"Look behind you" Perricone says at one point. He's indicating an elegant woman with a flawless face. "She's pretty, but she's had a face-lift. It's not natural, so it's not attractive," he says. "Her face muscles are all flat. She could have made changes in her diet to lift and tone her face muscles naturally."

Perricone is 54 years old, but he looks a lot younger. So for the next 72 hours I do what he recommends. I drink ten glasses of water a day and, twice a day, eat salmon, which is high in omega-3 fatty acid, a powerful antioxidant.

After three days I'm not sure how much more salmon I can eat, and I understand why some people tell Perricone that they'd rather smear the salmon on their face than continue with his program. But I feel great, and my face looks firmer and more alive, with better color.

Having seen the effects of aging arrested by diet, injection, and surgery, I decide that my next stop will be a nursing home, where I can investigate the results of aging allowed to take its natural course. I'm thinking mostly about wrinkles, but a phone call from my sister brings me back to where the life cycle of skin begins—the sense of touch.

Our mother, who is 86 years old and in poor health, has collapsed. When I walk into her hospital room, I lay my cheek on hers and lift her fingers into the palm of my hand. Although one of her eyes is partly open, the doctor says that she may not be able to see or hear me.

I try to comfort her by talking, singing songs from my childhood, or just sitting quietly. I'm not sure what she can sense, but her skin feels warm and normal. I keep my fingers on her arm or cheek, anything to let her know that she is not alone and that she is loved. I realize that our only unbroken connection now is through touch. We are skin to skin, warmth to warmth. According to the textbooks, transduction within the skin is transforming physical energy to neural energy. But something far more important is occurring. Love and memory are flowing through my skin and into her dreams.