Treatments For Psoriasis

Psoriasis is a chronic (long-lasting) skin disease characterized by scaling and inflammation. Scaling occurs when cells in the outer layer of the skin reproduce faster than normal and pile up on the skin's surface.

Psoriasis affects between 1 and 2 percent of the United States population, or about 5.5 million people. Although the disease occurs in all age groups and about equally in men and women, it primarily affects adults. People with psoriasis may suffer discomfort, including pain and itching, restricted motion in their joints, and emotional distress.

In its most typical form, psoriasis results in patches of thick, red skin covered with silvery scales. These patches, which are sometimes referred to as plaques, usually itch and may burn. The skin at the joints may crack. Psoriasis most often occurs on the elbows, knees, scalp, lower back, face, palms, and soles of the feet but it can affect any skin site. The disease may also affect the fingernails, the toenails, and the soft tissues inside the mouth and genitalia. About 15 percent of people with psoriasis have joint inflammation that produces arthritis symptoms. This condition is called psoriatic arthritis.

Recent research indicates that psoriasis is likely a disorder of the immune system. This system includes a type of white blood cell, called a T cell, that normally helps protect the body against infection and disease. Scientists now think that, in psoriasis, an abnormal immune system causes activity by T cells in the skin. These T cells trigger the inflammation and excessive skin cell reproduction seen in people with psoriasis.

In about one-third of the cases, psoriasis is inherited. Researchers are studying large families affected by psoriasis to identify a gene or genes that cause the disease. (Genes govern every bodily function and determine the inherited traits passed from parent to child.)

People with psoriasis may notice that there are times when their skin worsens, then improves. Conditions that may cause flareups include changes in climate, infections, stress, and dry skin. Also, certain medicines, most notably beta-blockers, which are used to treat high blood pressure, and lithium or drugs used to treat depression, may trigger an outbreak or worsen the disease.

Doctors usually diagnose psoriasis after a careful examination of the skin. However, diagnosis may be difficult because psoriasis can look like other skin diseases. A pathologist may assist with diagnosis by examining a small skin sample (biopsy) under a microscope.

There are several forms of psoriasis. The most common form is plaque psoriasis (its scientific name is psoriasis vulgaris). In plaque psoriasis, lesions have a reddened base covered by silvery scales.

Doctors generally treat psoriasis in steps based on the severity of the disease, the extent of the areas involved, the type of psoriasis, or the patient?s responsiveness to initial treatments. This is sometimes called the "1-2-3" approach. In step 1, medicines are applied to the skin (topical treatment). Step 2 focuses on light treatments (phototherapy). Step 3 involves taking medicines internally, usually by mouth (systemic treatment).

Treatments applied directly to the skin are sometimes effective in clearing psoriasis. Doctors find that some patients respond well to sunlight, corticosteroid ointments, medicines derived from vitamin D3, vitamin A (retinoids), coal tar, or anthralin. Other topical measures, such as bath solutions and moisturizers, may be soothing but are seldom strong enough to clear lesions over the long term and may need to be combined with more potent remedies.

Sunlight--Daily, regular, short doses of sunlight that do not produce a sunburn clear psoriasis in many people.

Ultraviolet (UV) light from the sun causes the activated T cells in the skin to die, a process called apoptosis. Apoptosis reduces inflammation and slows the overproduction of skin cells that causes scaling. Daily, short, nonburning exposure to sunlight clears or improves psoriasis in many people. Therefore, sunlight may be included among initial treatments for the disease. A more controlled form of artificial light treatment may be used in mild psoriasis (UVB phototherapy) or in more severe or extensive psoriasis (psoralen and ultraviolet A [PUVA] therapy). Long-term treatment is associated with an increased risk of squamous cell and melanoma skin cancers.

Corticosteroids--Available in different strengths, corticosteroids (cortisone) are usually applied twice a day. Short-term treatment is often effective in improving but not completely clearing psoriasis. If less than 10 percent of the skin is involved, some doctors will begin treatment with a high-potency corticosteroid ointment.

Calcipotriene--This drug is a synthetic form of vitamin D3. (It is not the same as vitamin D supplements.) Applying calcipotriene ointment (for example, Dovonex) twice a day controls excessive production of skin cells. Because calcipotriene can irritate the skin, however, it is not recommended for the face or genitals. After 4 months of treatment, about 60 percent of patients have a good to excellent response.

Coal tar--Coal tar may be applied directly to the skin, used in a bath solution, or used on the scalp as a shampoo. It is available in different strengths, but the most potent form may be irritating. It is sometimes combined with ultraviolet B (UVB) phototherapy. Compared with steroids, coal tar has fewer side effects, but it is messy and less effective and thus is not popular with many patients.

Topical retinoid--The retinoid tazarotene (Tazorac) is a fast-drying, clear gel that is applied to the surface of the skin. Although this preparation does not act as quickly as topical corticosteroids, it has fewer side effects. Because it is irritating to normal skin, it should be used with caution in skin folds. Women of childbearing age should use birth control when using tazarotene.

Salicylic acid--Salicylic acid is used to remove scales, and is most effective when combined with topical steroids, anthralin, or coal tar.

Bath solutions--People with psoriasis may find that bathing in water with an oil added, then applying a moisturizer, can soothe their skin. Scales can be removed and itching reduced by soaking for 15 minutes in water containing a tar solution, oiled oatmeal, Epsom salts, or Dead Sea salts.

Moisturizers--When applied regularly over a long period, moisturizers have a cosmetic and soothing effect. Preparations that are thick and greasy usually work best because they hold water in the skin, reducing the scales and the itching.

Retinoids--A retinoid, such as acitretin (Soriatane?), is a compound with vitamin A-like properties that may be prescribed for severe cases of psoriasis that do not respond to other therapies. Because this treatment also may cause birth defects, women must protect themselves from pregnancy beginning 1 month before through 3 years after treatment. Most patients experience a recurrence of psoriasis after acitretin is discontinued.

Researchers continue to search for genes that contribute to the inherited and other causes of psoriasis. Scientists are also working to improve our understanding of what happens in the body to trigger this disease. In addition, much research is focused on developing new and better treatments. Some of these experimental treatments, such as agents directed at the specific types of T cells involved, work to improve the disease with less overall suppression of the immune system.

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