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Diseases and Conditions
Special to CNN.com
Few things are more beautiful than healthy human skin. And few things are more burdened by symbolism or more wrapped up with people's identities. Qualities people attribute to skin — sensuality, youthfulness, vitality, beauty, even goodness — are also qualities they see in themselves. That skin often seems the outer reflection of the inner being may explain, at least in part, why problem skin is so distressing and why Americans spend billions of dollars a year on moisturizers and other cosmetics.
Ordinary dry skin (xerosis) usually isn't serious, but it can be uncomfortable and unsightly, turning plump cells into shriveled ones and creating fine lines and wrinkles long before you're due. More serious dry skin conditions, such as the inherited group of disorders called ichthyosis, can sometimes be disfiguring and may cause psychological distress to people living with them.
Fortunately, most dry skin results from environmental factors that can be wholly or partially controlled. These include exposure to hot or cold weather with low humidity levels and to wind, long-term use of air conditioning or central heating, excessive bathing, especially tub baths, and the use of strong soaps or detergents. Metabolic changes that occur with normal aging or with certain medical conditions also can affect the moisture content of your skin.
Chronic or severe dry skin problems may require a dermatologist's advice. But you can do a lot on your own to improve your skin, including drinking more water, showering less, and above all, moisturizing, moisturizing, moisturizing.
Signs and symptoms
Dry skin can be a temporary problem — one you experience only in winter, for example — or a lifelong concern. And although skin is often driest on your arms, lower legs and the sides of your abdomen, this pattern can vary considerably from person to person. What's more, signs and symptoms of dry skin depend on your age, your health status, your locale, the amount of time you spend outdoors, and the cause of the problem.
If you have dry skin due to environmental factors or normal aging, you're likely to experience one or more of the following:
- A feeling of tightness or tautness, especially after showering, bathing or swimming
- A loss of plumpness — your skin appears shrunken or dehydrated
- Skin that feels and looks rough rather than smooth
- Itching (pruritus) that sometimes may be intense
- Slight to severe flaking or scaling
- Fine lines or cracks
- Severe redness
- Deep fissures that may bleed
Specific dry skin conditions
Certain medical or age-related conditions can lead to dry skin problems that have unique signs and symptoms. These include:
- Ichthyosis vulgaris. Sometimes called fishscale disease or fish skin disease, ichthyosis vulgaris develops when skin cells fail to shed normally and instead accumulate in thick, dry scales. The scales are small, polygonal in shape and range in color from white to brown. They're most common on the lower legs and may be especially thick and dark over your shins. Ichthyosis vulgaris may also cause scalp flaking and deep, painful fissures on your palms and soles. Children with the inherited form of the disorder usually have normal skin at birth but develop scaling and roughness in the first few years of life. At times, ichthyosis vulgaris may disappear during the adult years, only to return as you age.
- Lamellar ichthyosis. This severe form of the disease is present at birth and lasts throughout life. Infants with lamellar ichthyosis are born encased in a filmy membrane that's shed after 10 to 14 days, revealing skin that's covered in scales. The scales can range from fine and white to thick and dark and generally occur over the entire body, although they may be larger on the legs. Lamellar ichthyosis can be extremely disfiguring and may cause great psychological suffering for children and adults with the disease.
- Asteatotic eczema (eczema craquele). This condition causes dry, scaly, deeply fissured skin that some doctors have described as resembling cracked porcelain or a dry riverbed. The affected skin may become inflamed, itchy and may bleed. Although asteatotic eczema can affect anyone, it's especially common in older adults, occurring primarily on the shins and sometimes on the thighs, hands and trunk.
- Psoriasis. A frustrating and sometimes disfiguring skin condition, psoriasis is marked by reddened skin with dry, silvery scales that sometimes resemble dandruff. In severe cases, your skin may crack, bleed and form pus-filled blisters. Psoriasis is a persistent, chronic disease that tends to flare periodically, and although it may go into remission, it usually remains active for years. It can occur at any age, but the onset is usually gradual and the diagnosis is commonly made between the ages of 15 and 35.
Because skin is so closely associated with beauty and sensuality, it's easy to forget the crucial role it plays in maintaining health. Although only about a tenth of an inch thick, your skin performs a number of essential functions, including protecting you from viruses, bacteria and environmental assaults, maintaining adequate hydration, and helping regulate body temperature.
Your skin consists of three layers:
- Epidermis. This outer layer, no thicker than a sheet of paper, both shields you from the world and presents you to it.
- Dermis. This thick middle layer makes up most of your skin. It contains collagen and elastin — fibers that give your skin strength, structure and elasticity.
- Subcutaneous layer. This layer, which is mainly fat, is the source of your skin's nerves and blood vessels as well as the roots of your hair follicles, oil glands and sweat glands.
Basal cells make up the base of the epidermis. They divide to form squamous cells that produce keratin, a hard protein that protects your skin from harmful substances and infection. As the basal cells divide, they push new squamous cells toward the surface of the epidermis, where they eventually shrink, flatten and die. These dead cells make up the stratum corneum, the outermost portion of the epidermis. Stratum corneum cells flake off every day and are continuously replaced by more cells. It usually takes about a month for skin cells to move from the basal layer to the stratum corneum.
But the stratum corneum is far more than a place where cells go to die. Instead, it's a dynamic structure that affects not only your skin's appearance but also its health. That's because the part of the stratum corneum between the cells is composed mainly of fats (lipids) such as ceramides, cholesterol and fatty acids. These fats form a strong, protective barrier that preserves the moisture in your body. Strip away the barrier and your skin cells lose the water they need to stay healthy and supple. Although many of the characteristics of dry skin are subjective — roughness, lack of radiance, tightness — scientists define dry skin based on specific, measurable changes in water and lipids in the stratum corneum.
A healthy stratum corneum is about 30 percent water, giving your skin resilience and elasticity. Most of the water is in the interior of the stratum corneum — in the outer layers, the water level depends on the amount of humidity in the air. The drier the air, the drier the outermost layer of skin.
Most cases of ordinary dry skin are due to environmental causes, such as:
- Weather. In general, your skin is driest in winter when temperatures and humidity levels plummet. Winter conditions also tend to make existing skin conditions worse. But the reverse may be true if you live in desert regions, where summer temperatures can top 110 F and humidity levels sink to 10 percent or less.
- Central heating and air conditioning. These may be technological marvels, but they're dermatological disasters. Central air and heating, wood burning stoves, space heaters and fireplaces all draw moisture out of the air and out of your skin.
- Too much 'cleanliness is next to godliness.' When it comes to your skin, water is a double-edged sword. Inside your skin, it keeps the cells plump and moist, but it has the opposite effect when you're immersed in it. Frequent showering or bathing, especially if you like your showers hot and your baths long, breaks down the lipid barriers in your skin. So does frequent swimming, particularly in heavily chlorinated pools.
- Harsh soaps and detergents. Many popular soaps and detergents strip lipids and water from your skin. Products containing fragrances and lauryl sulfates are harsher and more irritating than unscented products with sarcosinates, sulfosuccinates and cocoamphodiacetates. Deodorant and antibacterial soaps are usually the most damaging, as are many shampoos, which can dry out your scalp.
Certain diseases, metabolic problems and nutritional deficiencies can significantly alter the function and appearance of your skin:
- Ichthyosis. This group of inherited disorders occurs either because skin cells don't shed quickly enough or because they shed too quickly. Although the different forms of ichthyosis vary in their pattern of inheritance, the genes in which mutations occur, the age when they first appear and their physical manifestations, all cause dry, rough, scaly skin. In rare cases, ichthyosis may be acquired in adulthood rather than inherited, usually as a result of a systemic disease such as cancer or HIV infection. Certain drugs also may cause acquired ichthyosis.
- Asteatotic eczema. Several factors can contribute to asteatotic eczema, including certain neurologic disorders and exposure to harsh soaps, to chemicals or to cold, dry air. Older adults are especially prone to the condition because their skin may be compromised by dehydration, malnutrition or aging.
- Psoriasis. This skin condition is marked by a rapid buildup of rough, dry, dead skin cells that form thick scales. Normally, it takes about a month for new skin cells to move from the lowest layer of your skin, where they first form, to the stratum corneum, but in psoriasis the life cycle of skin cells speeds up. Although a defective gene for the disorder hasn't been discovered, most scientists believe psoriasis is an inherited condition that may be triggered or exacerbated by infections, skin injuries, a reaction to a vaccine or medication, stress, alcohol or long-time exposure to the sun or chemicals.
- Thyroid disorders. Hypothyroidism, a condition that occurs when your thyroid produces too few hormones, reduces the activity of your sweat and oil glands, leading to rough, dry skin.
- Alcohol and drugs. Alcohol and caffeine can visibly dry your skin. Prescription drugs such as diuretics, antihistamines and isotretinoin (Accutane) also have a drying effect.
- Nutritional deficiencies. A long-term lack of essential lipids, especially omega-3 fatty acids, can affect the integrity of your skin. So can a deficiency of the mineral zinc, which plays a key role in wound healing and in the metabolism of fatty acids and vitamin A.
- Dehydration. Severe diarrhea and vomiting, a high fever, profuse sweating during exercise or simply not drinking enough liquids can cause your body to lose more fluid than you take in. One of the first signs of dehydration is skin that has lost its elasticity.
Dry skin is a nearly universal problem, but certain factors make you more likely to develop tightness, flakiness and fine lines. These factors include:
- Your age. A healthy diet, consistent exercise and stress reduction can help you stay younger longer. Yet in spite of your best efforts, your skin is likely to change over time. As you age, your skin tends to become drier because your oil-producing glands are less active. And because cells move more slowly from the basal layer of the epidermis to the stratum corneum, your complexion can appear rough and dull. The slowed sloughing also causes cells to clump together in flakes or scales. Eventually, as the epidermis becomes thinner and more fragile and the subcutaneous layer of fat diminishes, your skin loses its strong protective function along with its youthful contours.
- Sun exposure. Like all types of heat, the sun dries your skin. Yet damage from ultraviolet (UV) radiation penetrates far beyond the epidermis. The most significant damage occurs deep in the dermis, where collagen and elastin fibers break down much more quickly than they should, leading to deep wrinkles and loose, sagging skin (solar elastosis).
- Your sex. Although everyone's skin changes with age, a man's skin tends to stay moist longer than a woman's does. Men experience a relatively small decrease in oil production until well into their 80s, whereas women's skin tends to become much drier after menopause.
- Diabetes. Diabetes can damage small blood vessels and nerves, increasing the likelihood of dry skin and of serious complications such as infection, cellulitis and gangrene.
- Winter weather. The combination of cold outdoor temperatures and dry indoor air takes a tremendous toll on your skin. Windy conditions and high altitudes only add to the problem.
- Hot baths and showers. Many people find long, hot showers and baths luxurious, but there's nothing glamorous about what they do to your skin. Strong soaps or soap-based cleansers, no matter how expensive or beautifully packaged, strip away even more oil and moisture.
- Smoking. Tobacco use doesn't cause dry skin per se, but it does accelerate wrinkling, especially around your eyes and upper lip. People who smoke tend to have more wrinkles than do nonsmokers who are the same age and have similar histories of sun exposure. The amount of skin damage increases with the number of years and cigarettes smoked.
When to seek medical advice
Most cases of dry skin respond well to self-care measures. See your doctor if:
- Your skin doesn't improve in spite of your best efforts
- Dryness and itching keep you from sleeping
- You have open sores or an infection from scratching
- You have large areas of scaling or peeling skin
Screening and diagnosis
Your doctor is likely to conduct a thorough physical exam and to question you about your medical history, including when your dry skin started, what factors make it better or worse, your bathing habits, your diet and how you care for your skin.
You may have certain diagnostic tests if your doctor suspects that your dry skin is the result of an underlying medical condition such as hypothyroidism or diabetes. In addition, genetic tests can help identify some, but not all, of the more than 20 types of ichthyosis. If tests reveal a more serious condition, you may be referred to other doctors, including a dermatologist, who specializes in skin disorders.
Dry skin that's not cared for can lead to:
- Eczema. This condition causes redness, cracking and inflammation.
- Folliculitis. This is an inflammation of your hair follicles.
- Cellulitis. This is a potentially serious bacterial infection of the skin's underlying tissues.
These complications are most likely to occur when your skin's normal protective mechanisms are severely compromised. For example, you might scratch an itchy patch of skin until it cracks and bleeds, opening the way for invading bacteria. But your skin can also crack and bleed without you ever lifting a finger.
In that case, the process might work something like this: You take a long, hot bath every evening, but don't apply a moisturizer afterward. As a result, the stratum corneum loses water and the cells shrink, losing their normal plumpness. This stretches your skin, decreasing its elasticity and eventually causing severe cracks or fissures. Deep fissures rupture tiny blood vessels in your skin, which leads to bleeding. Meanwhile, loss of tone in the top layer of skin creates fluid buildup in the dermis, putting additional stress on the epidermis and setting the stage for inflammation and infection.
In most cases, dry skin problems respond well to self-care measures. If you have more serious diseases such as ichthyosis or psoriasis, your doctor may prescribe prescription creams and ointments or other treatments in addition to home care.
Although it may not be possible to achieve flawless skin, the following measures can help keep your skin moist and healthy:
- Wash 'n' go. For most people, a once-daily bath or shower is enough to maintain good hygiene. If your skin is very dry, bathing every other day may be best. Keep in mind that the longer you're in water, the more protective oils you lose. For that reason, and because it takes just a few minutes to wash thoroughly, limit baths and showers to 15 minutes or less. And use warm, rather than hot, water. Less is more when it comes to washing your face, too. Although it may be difficult to break the habit of cleansing your face morning and evening, once a day should be enough to remove dirt and oil. If your skin doesn't feel fresh on this abbreviated schedule, try rinsing with cool water in the morning and using a cleanser only at night.
- Avoid harsh, drying soaps. If you have dry skin, it's best to use cleansing creams or gentle skin cleansers and bath or shower gels with added moisturizers. These don't have to be expensive, celebrity-endorsed brands. Many dermatologists recommend Cetaphil and Aveeno cleansers, for instance, which are reasonably priced and available in most drugstores. Department store cleansers are considerably pricier, but most cosmetics companies offer free samples that you can try. If you just don't feel clean without soap, choose mild soaps that have added oils and fats, such as Neutrogena, Basis or Dove. Avoid deodorant and antibacterial detergents, which are especially harsh. You might want to experiment with several brands until you find one that works particularly well for you. A good rule of thumb is that your skin should feel soft and smooth after cleansing, never tight or dry. Try to use soaps and cleansers of any type only on your face, underarms, genital area, and your hands and feet.
- Don't scrub, rub or soak in the tub. You've heard that last one before, but it bears repeating. As for the first two, it's best to use your hands or a cleansing sponge on your face instead of a washcloth. Although a cloth can help remove (exfoliate) dead cells, it may be too irritating for very dry skin. After washing, pat or blot your skin until it's just barely dry, then moisturize immediately to help trap water in the surface cells.
- Moisturize, moisturize, moisturize. Nearly 9,000 cosmetic, hair, and skin care products were introduced in the United States in 2003 alone. Many of these were moisturizers of one sort or another. And it's not only baby boomer women with lots of disposable income who are driving this trend — men, teens and even children account for an increasingly large share of the skin care market. What's more, most contemporary moisturizers bear little resemblance to your mother's cold cream. Instead, they're highly sophisticated products that tread the fine line between cosmetics and drugs. Many contain ingredients that claim to boost your body's production of collagen and elastin, plump up wrinkles and fill in lines, paralyze muscles, unblock pores, and exfoliate dead skin cells.
All about moisturizers
Given the array of products, the broad audience to which they're targeted, and the even broader price range — moisturizers can cost from less than $10 to more than $500 — how do you choose the right one?
The best place to start may be to understand the different types of moisturizing agents and what they do. On the most basic level, moisturizers hold water in the stratum corneum. They also act as a temporary barrier, allowing damaged surface cells time to repair themselves. Many moisturizers contain some combination of humectants and emollients, as well as other ingredients:
- Humectants.These are substances such as urea and glycerin that attract water when you apply them to your skin. But humectants need high humidity levels to be effective, and even then, any water added to the surface of your skin tends to evaporate quickly.
- Emollients. These fill in the spaces between the cells in the stratum corneum, helping replace lipids and thus smoothing and lubricating rough skin. Emollients are water-in-oil emulsions, which means that a small amount of water is dissolved in an occlusive oil, such as petrolatum, mineral oil or natural plant oils. If you have mature or very dry skin, your best choice may be a water-in-oil moisturizer, which will be tend to be heavier and richer than other moisturizers. Most creams labeled night creams have water-in-oil formulations. Oil-in-water moisturizers, on the other hand, are primarily water and have a light, nongreasy feel. These may be a better option if you are younger, your skin tends to break out, or you have mild or occasional dryness.
- Vitamin A. Retinol and retinyl palmitate are forms of vitamin A that may be converted in the skin into retinoic acid, the active ingredient in the prescription creams Retin-A, Renova and Tazorac. Retinoic acid helps keep pores clear and has been shown to improve some of the damage caused by sun exposure.
- Alpha hydroxy acids. These encourage skin cells to exfoliate properly and have proved effective in treating some forms of ichthyosis.
- Antioxidants. Vitamins such as C and E can help protect and repair skin exposed to pollutants and UV rays.
Keep in mind that many of these ingredients can be drying and irritating to your skin, and you may want to talk to your dermatologist before trying products that contain them. Preservatives and fragrances also can dry and irritate sensitive skin, so it's best to look for creams that are fragrance-free and contain as few preservatives as possible. Preservatives that seem to cause problems for many people include quaternium-15, imidazolidinyl urea and propylene glycol.
Many moisturizers also contain sunscreen, hydrating your skin and protecting it from UVA and UVB radiation in one easy step. But combination creams may not always moisturize or protect against sun damage as well as individual products do. In addition, some companies make extra-rich moisturizers that claim to shield you from the elements better than ordinary creams do. With names like flight cream and high-altitude cream, they may or may not offer extra protection against cold, dry air.
Apply any moisturizer as often as needed, especially after bathing, showering or washing your face, before exercising outdoors in cold weather, and every time you wash your hands. Although often ignored, your hands are more exposed to the elements, to soaps and to chemicals than is any other part of your body.
These other measures may also help keep your skin healthy:
Chapped lips: What is the best remedy?
- Moisturize your house. With your home thermostat set high and your central heat blasting, your home may stay warm and cozy. But hot, dry indoor air can parch sensitive skin and worsen itching and flaking. As a rule of thumb, keep your house between 68 and 75 F and use a humidifier to maintain moisture levels at 40 percent to 50 percent. Tabletop humidifiers usually moisturize the air in a single room and require frequent fillings, sometimes several times a day. They also need careful cleaning to prevent the growth of bacteria and fungi in the tank. The bedroom may be the best place for this type of humidifier — your skin is hydrated as you sleep. Although it's a more costly option, you may want to consider a humidifier that's built into your forced air heating and cooling system, especially if you have severely dehydrated skin or live in a climate that's dry year-round.
- Choose fabrics your skin loves. Natural fibers such as cotton and silk feel wonderful and allow your skin to breathe. But wool, although it certainly qualifies as natural, can irritate even normal skin. If your skin is already sensitive and dry, you may need to forgo cashmere sweaters and pashmina scarves and choose other fabrics for winter. And when you wash your clothes, try to use detergents without dyes or perfumes, both of which can irritate your skin. Look for these products in the grocery store or choose fragrance-free detergents in natural foods stores.