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Questions and Answers about Psoriasis

This booklet contains general information about psoriasis. It describes what psoriasis is, what causes it, and what the treatment options are. If you have further questions after reading this booklet, you may wish to discuss them with your doctor.

What Is Psoriasis?

Psoriasis is a chronic (long-lasting) skin disease of scaling and inflammation that affects 2 to 2.6 percent of the United States population, or between 5.8 and 7.5 million people. Although the disease occurs in all age groups, it primarily affects adults. It appears about equally in males and females. Psoriasis occurs when skin cells quickly rise from their origin below the surface of the skin and pile up on the surface before they have a chance to mature. Usually this movement (also called turnover) takes about a month, but in psoriasis it may occur in only a few days. In its typical form, psoriasis results in patches of thick, red (inflamed) skin covered with silvery scales. These patches, which are sometimes referred to as plaques, usually itch or feel sore. They most often occur on the elbows, knees, other parts of the legs, scalp, lower back, face, palms, and soles of the feet, but they can occur on skin anywhere on the body.

The disease may also affect the fingernails, the toenails, and the soft tissues of the genitals and inside the mouth. While it is not unusual for the skin around affected joints to crack, approximately 1 million people with psoriasis experience joint inflammation that produces symptoms of arthritis. This condition is called psoriatic arthritis.

How Does Psoriasis Affect Quality of Life?

Individuals with psoriasis may experience significant physical discomfort and some disability. Itching and pain can interfere with basic functions, such as self-care, walking, and sleep. Plaques on hands and feet can prevent individuals from working at certain occupations, playing some sports, and caring for family members or a home. The frequency of medical care is costly and can interfere with an employment or school schedule. People with moderate to severe psoriasis may feel self-conscious about their appearance and have a poor self-image that stems from fear of public rejection and psychosexual concerns. Psychological distress can lead to significant depression and social isolation.

What Causes Psoriasis?

Psoriasis is a skin disorder driven by the immune system, especially involving a type of white blood cell called a T cell. Normally, T cells help protect the body against infection and disease. In the case of psoriasis, T cells are put into action by mistake and become so active that they trigger other immune responses, which lead to inflammation and to rapid turnover of skin cells. In about one-third of the cases, there is a family history of psoriasis. Researchers have studied a large number of families affected by psoriasis and identified genes linked to 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 infections, stress, and changes in climate that dry the skin. Also, certain medicines, including lithium and betablockers, which are prescribed for high blood pressure, may trigger an outbreak or worsen the disease.

How Is Psoriasis Diagnosed?

Occasionally, doctors may find it difficult to diagnose psoriasis, because it often looks like other skin diseases. It may be necessary to confirm a diagnosis by examining a small skin sample under a microscope. There are several forms of psoriasis. Some of these include:

How is Psoriasis Treated?

Doctors generally treat psoriasis in steps based on the severity of the disease, size of the areas involved, type of psoriasis, and the patient's response 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 uses light treatments (phototherapy). Step 3 involves taking medicines by mouth or injection that treat the whole immune system (called systemic therapy).

Over time, affected skin can become resistant to treatment, especially when topical corticosteroids are used. Also, a treatment that works very well in one person may have little effect in another. Thus, doctors often use a trial-and-error approach to find a treatment that works, and they may switch treatments periodically (for example, every 12 to 24 months) if a treatment does not work or if adverse reactions occur.

Topical Treatment

Treatments applied directly to the skin may improve its condition. Doctors find that some patients respond well to ointment or cream forms of corticosteroids, vitamin D3, retinoids, coal tar, or anthralin. Bath solutions and moisturizers may be soothing, but they are seldom strong enough to improve the condition of the skin. Therefore, they usually are combined with stronger remedies.

Light Therapy

Natural ultraviolet light from the sun and controlled delivery of artificial ultraviolet light are used in treating psoriasis.

Systemic Treatment

For more severe forms of psoriasis, doctors sometimes prescribe medicines that are taken internally by pill or injection. This is called systemic treatment. Recently, attention has been given to a group of drugs called biologics (for example, alefacept and etanercept), which are made from proteins produced by living cells instead of chemicals. They interfere with specific immune system processes.

Combination Therapy

There are many approaches for treating psoriasis. Combining various topical, light, and systemic treatments often permits lower doses of each and can result in increased effectiveness. Therefore, doctors are paying more attention to combination therapy.

Psychological Support

Some individuals with moderate to severe psoriasis may benefit from counseling or participation in a support group to reduce self-consciousness about their appearance or relieve psychological distress resulting from fear of social rejection.

What Are Some Promising Areas of Psoriasis Research?

Significant progress has been made in understanding the inheritance of psoriasis. A number of genes involved in psoriasis are already known or suspected. In a multifactor disease (involving genes, environment, and other factors), variations in one or more genes may produce a greater likelihood of getting the disease. Researchers are continuing to study the genetic aspects of psoriasis. Since discovering that inflammation in psoriasis is triggered by T cells, researchers have been studying new treatments that quiet immune system reactions in the skin. Among these are treatments that block the activity of T cells or block cytokines (proteins that promote inflammation). Several of these drugs are awaiting approval by the U.S. Food and Drug Administration (FDA).

Advances in laser technology are making it possible for doctors to experiment with laser light treatment of localized plaques. A UVB laser was recently tested in a study that was conducted at several medical centers. Although improvements in the skin were noted, this treatment is not without possible side effects. In some patients, the skin became inflamed, blistered, or discolored following treatment.

Where Can People Find More Information About Psoriasis?

National Institute of Arthritis and Musculoskeletal and Skin Diseases
NIAMS/National Institutes of Health
1 AMS Circle
Bethesda, MD 20892-3675
Phone: 301-495-4484
TTY: 301-565-2966
Fax: 301-718-6366
E-mail: niamsinfo@mail.nih.gov
www.niams.nih.gov/

NIAMS provides information about various forms of skin diseases; arthritis and rheumatic diseases; and bone, muscle, and joint diseases. It distributes patient and professional education materials and also refers people to other sources of information. Additional information and updates can be found on the NIAMS Web site.

American Academy of Dermatology
P.O. Box 4014
Shaumburg, IL 60168-4014
Phone: 847-330-0230 or 888-462-DERM (3376) (free of charge)
Fax: 847-330-0050
www.aad.org

This national professional association for dermatologists has a Web site (PsoriasisNet) that contains basic information on psoriasis for lay readers. Also included are press releases, answers to frequently asked questions, information updates, and lists of dermatologists.

National Psoriasis Foundation
6600 SW 92nd Avenue, Suite 300
Portland, OR 97223-7195
Phone: 503-244-7404 or 800-723-9166 (free of charge) Fax: 503-245-0626
E-mail: getinfo@npfusa.org
www.psoriasis.org

The National Psoriasis Foundation provides physician referrals and publishes pamphlets and newsletters that include information on support groups, research, and new drugs and other treatments. The foundation also promotes community awareness of psoriasis.

Acknowledgments

The NIAMS gratefully acknowledges the assistance of Kevin D. Cooper, M.D., University Hospitals of Cleveland/Case Western Reserve University, Ohio; Gerald Krueger, M.D., University of Utah, Salt Lake City; Mark Lebwohl, M.D., The Mount Sinai Medical Center, New York, New York; Laurence H. Miller, M.D., P.A., Chevy Chase, Maryland; Alan N. Moshell, M.D., NIAMS; Robert Stern, M.D., Beth Israel Deaconess Medical Center, Boston, Massachusetts; and the National Psoriasis Foundation in the preparation of this and previous versions of this booklet.

The mission of the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), a part of the Department of Health and Human Services' National Institutes of Health (NIH), is to support research into the causes, treatment, and prevention of arthritis and musculoskeletal and skin diseases, the training of basic and clinical scientists to carry out this research, and the dissemination of information on research progress in these diseases. The National Institute of Arthritis and Musculoskeletal and Skin Diseases Information Clearinghouse is a public service sponsored by the NIAMS that provides health information and information sources. Additional information can be found on the NIAMS Web site at www.niams.nih.gov.

NIH Publication No. 03-5040


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