Psoriasis

Psoriasis is a persistent skin disease that got its name from the Greek word for "itch." The skin becomes inflamed, producing red, thickened areas with silvery scales, most often on the scalp, elbows, knees, and lower back.

In some cases, psoriasis is so mild that people don't know they have it. At the opposite extreme, severe psoriasis may cover large areas of the body. Doctors can help even the most severe cases.

Psoriasis cannot be passed from one person to another, though it is more likely to occur in people whose family members have it. In the United States two out of every hundred people have psoriasis (four to five million people). Approximately 150,000 new cases occur each year.

What Causes Psoriasis?

The cause is unknown. However, recent discoveries point to an abnormality in the functioning of key white cells in the blood stream triggering inflammation in the skin. This causes the skin to shed itself too rapidly, every three to four days.

People often notice new spots 10 to 14 days after the skin is cut, scratched, rubbed, or severely sunburned. Psoriasis can also be activated by infections, such as strep throat, and by certain medicines. Flare-ups sometimes occur in the winter, as a result of dry skin and lack of sunlight.

Types of Psoriasis

Psoriasis comes in many forms. Each differs in how bad it is, how Iong it lasts, where it is, and in the shape and pattern of the scales. The most common form begins with little red bumps. Gradually these grow larger and scales form. While the top scales flake off easily and often, scales below the surface stick together. When they are removed, the tender, exposed skin bleeds. These small red areas then grow, sometimes becoming quite large.

• Elbows, knees, groin and genitals, arms, legs, scalp, and nails are the areas most commonly affected by psoriasis. It will often appear in the same place on both sides of the body.
  

• Nails with psoriasis have tiny pits on them. Nails may loosen, thicken or crumble and are difficult to treat.
  

• Inverse psoriasis occurs in the armpit, under the breast and in skin folds around the groin, buttocks, and genitals.
  

• Guttate psoriasis usually affects children and young adults. It often shows up after a sore throat, with many small, red, drop-like, scaly spots appearing on the skin. It often clears up by itself in weeks or a few months.
  

• About seven percent of psoriasis patients also have arthritis, which fortunately is not too severe in most people. In some people, the arthritis is worst when the skin is very involved. Sometimes the arthritis improves when the condition of the patient's skin improves.

How Is Psoriasis Diagnosed?

Dermatologists diagnose psoriasis by examining the skin, nails, and scalp. They may need to take a skin biopsy to examine under the microscope.

How Is Psoriasis Treated?

The goal is to reduce inflammation and to slow down rapid skin cell division. Moisturizing creams and lotions loosen scales and help control itching. Special diets have not been successful in treating psoriasis.

Treatment is based on a patient's health, age, lifestyle, and the severity of the psoriasis. Different types of treatments and several visits to the dermatologist may be needed. There are many ways to treat Psoriasis.

The doctor may prescribe medications to apply on the skin containing cortisone-like compounds, synthetic vitamin D, tar, or anthralin. These may be used in combination with natural sunlight or ultraviolet light. The most severe forms of psoriasis may require oral medications, with or without light treatment.

Sunlight exposure helps the majority of people with psoriasis but it must be used cautiously. Ultraviolet light therapy may be given in a dermatologist's office, a psoriasis center or a hospital.

Types of Treatment

Steriods (Cortisone) - Cortisone creams, ointments, and lotions may clear the skin temporarily and control the condition in many patients. Weaker preparations should be used on more sensitive areas of the body such as the genitals, groin, and face. Stronger preparations will usually be needed to control lesions on the scalp, elbow, knees, palms and soles, and parts of the torso and may need to be applied under dressings. These must be used cautiously and with the dermatologist's instruction. Side effects of the stronger cortisone preparations include thinning of the skin, dilated blood vessels, bruising, and skin color chances. Stopping these medications suddenly may result in a flare-up of the disease. After many months of treatment, the psoriasis may become resistant to the steroid preparations.

The dermatologist may inject cortisone in difficult-to-treat spots. These injections must be used in very small amounts to avoid side effects.

Scalp Treatment - The treatment for psoriasis of the scalp depends on the seriousness of the disease, hair length, and the patient's lifestyle. A variety of non-prescription and prescription shampoos, oils, solutions, and sprays are available. Most contain coal tar or cortisone. The patient must take care to avoid harsh shampooing and scratching the scalp.

Anthralin is a medication that works well on tough-to-treat thick patches of psoriasis. It can cause irritation and temporary staining of the skin and clothes. Newer preparations and methods of treatment have lessened these side effects.

Vitamin D
A synthetic Vitamin D, calcipotriene, is now available in prescription form. It is useful for individuals with localized psoriasis and can be used with other treatments. Limited amounts should be used to avoid side effects. Ordinary Vitamin D, as one would buy in a drug store or health food store, is of no value in treating psoriasis.

Coal Tar - For more than 100 years, coal tar has been used to treat psoriasis. Today's products are greatly improved and less messy. Stronger prescriptions can be made to treat difficult areas.

Light Therapy - Sunlight and ultraviolet light slow the rapid growth of skin cells. Though ultraviolet light or sunlight can cause skin wrinkling, eye damage, and skin cancer, light treatment is safe and effective under a doctor's care. People with psoriasis all over their bodies may require treatment in a medically approved center equipped with light boxes for full body exposure. Psoriasis patients who live in warm climates may be directed to carefully sunbathe. Seek the advice of a dermatologist before self-treating with natural or artificial sunlight.

Because psoralen remains in the lens of the eye, patients must wear UVA blocking eyeglasses whenever using sunlight for illumination from the time of exposure to psoralen until sunset that day. PUVA treatments over a long period increase the risk of skin aging, freckling, and skin cancer. PUVA treatment must be monitored very carefully by dermatologists and their staff.

There are 3 different oral medications used to treat severe Psoriasis: methotrexate, acetretin, and aydosporine. Your dermatologist will determine if any of these medications are indicated.

New Therapies Under Investigation

The above treatments alone or in combination can clear or greatly improve psoriasis in most cases, but no treatment permanently "cures" it. Dermatologists and other researchers are continually testing new drugs and treatments.

© 1994 American Academy of Dermatology