October 15, 2018
Woman rubbing lotion on her skin.

The Skinny on Skin: From Dry Skin to Psoriasis

by Wellness Letter  

Your skin is your friend, safeguarding everything in­­side your body, keeping you comfortable, and serving as a barrier against infection. Returning the favor starts with protecting it from the sun. When outdoors on sunny days, wear a wide-brimmed hat, long-sleeved shirts, and long pants. You can even purchase clothing with built-in ultraviolet (UV) protection or laundry additives that wash in sunblock. And, of course, use sunscreen.

Other lifestyle habits can have a positive effect on your skin, too. The same healthy diet choices that are good for your other organs benefit the skin: fruits, vege­tables, whole grains instead of refined grains, unsaturated rather than saturated fats. Some evidence suggests that the omega-3 fats in fish may also be good for the skin.

Although your skin is almost one-third water, the skin benefits of drinking at least six to eight glasses of water a day have likely been exaggerated. It’s important to stay hydrated, but there’s little scientific evidence that adding extra water to your insides makes your outsides feel less dry or look more youthful.

Healthy skin is yet another reason to kick the smoking habit. Smoking narrows the capillaries that carry blood to the skin and damages the collagen and elastin in the dermis that keep your skin elastic and strong—and the chronic pursing of the lips to hold a cigarette increases wrinkling.

How dry I am

Dry skin can occur in people of all ages, although it is more commonly seen in older adults who have lost natural moisture and oil from their skin. Signs and symptoms include itching, chapping, scaling, flaking, and cracking.

Preventing and treating dry skin starts with how you clean your skin. In general, take short baths or showers using lukewarm water, and do so no more than once a day. Avoid aggressive or excessive scrubbing. Choose a milder soap and use as little as you can; for most bathing, using soap only under your armpits, around the groin, and on your face should be enough. All soaps (even ones calling themselves “natural”) are created by the action of a strong alkali on fats or oils; as a result, soaps end up a little bit alkaline. Their use alkalizes the normally mildly acidic skin, damaging its natural moisture barrier. In contrast, detergents—which include shower gels, body washes, most shampoos, and synthetic detergent bar cleansers like Dove, Olay, or Cetaphil—have a pH closer to that of normal skin and are less irritating.

Cotton is easier on your skin than wool, which tends to be rough and can rub and catch on scaly skin, leading to a vicious cycle of itching and scratching. Permanent-press and wrinkle-resistant fabrics may have formaldehyde or other irritating chemicals in their finish. Wash new clothing and towels before using them.

If you have dry skin, try not to scratch, which may irritate the skin further. Don’t use alcohol-based products to combat itching, since alcohol dries out skin.

Contact your doctor if you develop a severe rash or patches of dry skin accompanied by itching and redness (dermatitis) or if you are bothered by persistent itching.

Is it eczema?

More than 30 million Americans have eczema, in which the skin becomes red, itchy, and inflamed. (The terms “eczema” and “dermatitis” are often used interchangeably.) Atopic dermatitis, the most common form of eczema, is common in children but also affects adults, who can develop it even if they never had it when they were young. There are several other forms of eczema, with varying symptoms and causes including: contact dermatitis, dyshidrotic eczema, nummular eczema, seborrheic dermatitis, and stasis dermatitis.

Even within one type of eczema, symptoms may differ from one person to an­­other. In general, however, eczema is characterized by flare-ups of patches suggestive of the word’s original Greek meaning, “to boil over.” These reddened, in­­­­flamed areas typically itch. In some cases, the itching becomes so severe that people scratch until they bleed and make their eczema even worse.

Other signs of eczema include: dry, scaly and sensitive skin; areas of swelling; fluid-filled blisters; oozing or crusting; cracking of the skin (especially in skin folds such as those behind the ears); rough and leathery skin; and dark-colored patches.

You may have only some of these symptoms. Children most often get eczema patches on their faces, especially the chin and cheeks. In adults, eczema often flares up on the back of the knees, but it may appear on different areas of the body at different times, including the face, hands, feet, and inner elbow.

Eczema can be triggered by anything that irritates the skin, including certain clothing fibers. Atopic dermatitis is often associated with asthma or hay fever or a family history of these conditions. Symptoms of atopic dermatitis can be exacerbated by irritants such as soap, household chemicals, dust, and even some foods.

The same skin-care strategies that help prevent dry skin can be beneficial against eczema. Over-the-counter topical hydrocortisone and oral antihistamines may also provide relief. If your symptoms persist or worsen, visit a health care provider who can determine which type of eczema you have and how best to treat it. A variety of drugs may be prescribed, ranging from steroid ointments and creams to drugs that modify the immune system.

Treating seborrheic dermatitis

A common form of eczema, seborrheic dermatitis is a chronic inflammatory skin condition that results in a red rash with white flaking scales. (Some dermatologists refer to the flaking as “seborrhea,” while others use “seborrheic dermatitis” and “seborrhea” interchangeably.) It occurs where there are sebaceous (oil-producing) glands—most abundantly on the scalp (where it’s called dandruff), face (especially the eyebrows, forehead, nose creases, beard or mustache, behind the ears), under the arms, around the groin, and in other skin folds. There may at times be itching or burning.

People with suppressed immunity (as with HIV infection) or some neurological conditions (like Parkinson’s disease) are more susceptible. There may be a genetic or hormonal component. Emotional stress, certain medications, and changes in season and humidity may trigger flare-ups. Some cases may be caused by sensitivity to yeast on the skin, although it is not contagious.

There’s no cure, but there are ways to control seborrheic dermatitis. Treat acute flare-ups as early as possible. You can try an over-the-counter corticosteroid cream or lotion, or your doctor may prescribe stronger concentrations. But these can thin the skin over time and cause worsening of the condition when you stop, so use the lowest strength for the shortest time. Sometimes they simply do not work.

For long-term treatment, your doctor may prescribe a topical anti-yeast medication (such as ketoconazole or ciclopirox). Some dermatologists also recommend topical immunosuppressive drugs (such as tacrolimus or pimecrolimus).

Medicated shampoos that contain pyrithione zinc, selenium sulfide, salicylic acid, ketoconazole, or sulfur may help control seborrheic dandruff. If these don’t help enough, your doctor may recommend a prescription shampoo or other product.

Understanding psoriasis

Another common skin condition, psoriasis is a non-contagious but persistent autoimmune disorder that occurs when the normal cycle of skin cell growth and replacement is disrupted. Normally, new skin cells rise from the deepest layer of skin to the top layer—the epidermis—and replace dead skin cells, which are shed. This process ordinarily takes about 28 days. In areas marked by psoriasis, the process has been accelerated, taking place in only three or four days—and as a result excess cells accumulate. This causes the characteristic patches of dry, raised, itchy, and inflamed skin with white flaking scales, usually appearing on the scalp, lower back, elbows, or knees.

Eruptions of psoriasis tend to peak in two different age groups: people ages 30 to 39 and those ages 50 to 69. The condition can increase and decrease in severity, often for no apparent reason, although it is often more severe during the winter, perhaps because of drier air and reduced sunlight. There are different types of psoriasis, and in worst cases it can be associated with a form of arthritis and be disabling.

No one knows what causes psoriasis. Strong evidence points to a genetic component: 40 percent of patients have a family history of the condition. Factors that can increase the risk of psoriasis or make symptoms worse include alcohol, smoking, obesity, stress, anxiety, a recent bacterial or viral infection, certain medications, sunburn, and possibly vitamin D deficiency. There is, however, no conclusive link between diet and psoriasis.

Psoriasis increases the risk of numerous conditions, including cardiovascular disease, eye disorders, and inflammatory bowel disease.

Controlling psoriasis

Psoriasis is not curable, but it can be controlled. It’s important to consult a dermatologist, since psoriasis can be confused with other skin conditions. Your dermatologist is likely to recommend or prescribe various medications, such as topical corticosteroids, vitamin D analogues (calcipotriene, calcitriol), anthralin to slow skin cell growth, vitamin A derivatives called retinoids, calcineurin inhibitors (tacrolimus, pimecrolimus), salicylic acid, and coal tar. In more severe cases, ultraviolet treatments or a new class of injectable (or infused) medications called biologics might be indicated.

The following home remedies can complement any treatments your doctor recommends. Only trial and error will determine which are most effective for you. Improvement can take a few weeks or as long as several months.

  • Get some sun. Most people should guard against too much sun, but to minimize the effects of psoriasis, it may help to expose the affected areas to the sun or a special light box (sometimes with medication), as directed by your dermatologist. Proceed cautiously, staying in direct sunlight for 15 to 30 minutes a day. About 80 percent of people with psoriasis will see improvement in three to six weeks.
  • Moisturize your skin. Apply moisturizing skin creams liberally to keep skin moist and less likely to crack.
  • Take a soak. Special bath solutions containing oatmeal, various oils, or Epsom salts may offer symptomatic relief for psoriasis. Soak for 15 minutes in warm water to soothe the skin and encourage healing. Moisturize when you get out.
  • Remove skin scales. Nonprescription creams and ointments that contain salicylic acid, lactic acid, or urea can help to soften and remove scales. Coal tar gels, also available in the pharmacy without prescription, can slow down the rate at which skin cells are produced, thereby improving psoriasis symptoms. Some coal tar products can be irritating to the skin, so test on a small area first. Also, coal tar can make your skin more sensitive to sunlight, so be sure to wash it off before going out in the sun; it’s also messy and can stain.
  • Get some scalp relief. For psoriasis plaques on the scalp, a special softening gel that contains salicylic acid is available over the counter. Apply it to the scalp at night according to directions, and wash it out in the morning with a medicated dandruff shampoo.
  • Consider an OTC topical corticosteroid cream, which may help relieve itching. Discuss this with your doctor first.

This article first appeared in the UC Berkeley Wellness Letter.

Also see The Best Moisturizers for Eczema.