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Skin Care and Diseases

Psoriasis

According to the National Institute of Arthritis and Musculoskeletal and Skin Diseases, between 5.8 and 7.5 million people in the United States suffer from a chronic skin condition called psoriasis (pronounced sore-EYE-ah-sis).

What is Psoriasis?

Psoriasis is a skin disorder where cells in the top layer of skin divide and replicate up to 10 times faster than in normal skin. This leads to areas with well defined thick (from the increased number of skin cells), red (from increased blood flow to the lesion), and scaling (white thick flakes) lesions and occasionally pus bumps. The skin can become, itchy, painful, and bleed at times.

Any area of the body can get the lesions, the most common place is the elbows, knees, buttock, scalp and ears. Mild psoriasis of the scalp if often confused with severe dandruff. When the nails become involved it can be confusing to tell psoriasis apart from fungus infection of the nail. Sometimes only the palms and soles, or the private areas are involved. To determine if someone has psoriasis, doctors usually examine the full skin surface to make the diagnosis based on appearance. Sometimes a piece of skin has to be cut and viewed under a microscope (also called a biopsy).

About 5-20% of patients who have skin psoriasis also have inflammation of their joints leading to psoriatic arthritis. This type of inflammation can cause pain, swelling, and stiffness of the joints or tendons and in some cases "sausage shaped" digits and other arthritic deformities. The most common sites of the arthritis are in the fingers, toes, wrists, ankles and lower back, although any joint can be involved.

It is not known what causes psoriasis but it is known that certain cells of the immune system (T-cells) and proteins that cause inflammation are overactive and cause the psoriasis lesions. It is important to note that psoriasis is not contagious and can not be spread from person to person. Scientists believe that genes play a role in why many people have psoriasis. This would explain why psoriasis often runs in families. Studies are still being conducted to determine exactly how these genes come into play with psoriasis.

There are a several forms of psoriasis, which are characterized by the type of lesions or degree of inflammation:

Aggravating factors for psoriasis include stress, infection (strep throat and other infections), certain medications, cold weather and climate change, and trauma. The role of food and diet have not been well defined and appear to vary from individual to individual.

Although there is no cure for psoriasis, there are many treatment options available to control the psoriasis. Patients must realize that no treatment is full-proof and that multiple different treatments may be needed over the years to keep psoriasis under control. Psoriasis may go into remission (lesion free periods) in some patients for months to years on its own or with certain treatments. For many patients, some form of treatment or another is needed to keep the psoriasis controlled.

Treatment of Psoriasis

There are three steps that doctors usually take in the treatment of psoriasis:

  1. Topical or localized treatment
  2. Light therapy
  3. Systemic treatment

Topical or localized treatments available for psoriasis patients are corticosteroids (there are multiple different strengths), vitamin D3 (such as calcipotriene), retinoids (synthetic vitamin A), coal tar, anthralin, and salicylic acid. Some bath solutions and moisturizers can also help soothe the skin. Sometimes steroids are injected directly into the lesions for longer local control. Laser therapy with vascular lasers and excimer lasers can be beneficial in some patients with limited psoriasis.

Light therapy is the second step in treating psoriasis. Ultraviolet rays from the sun and other phototherapy sources can help those with psoriasis by helping to decrease the overactive T cells. The four most common forms of light therapy are broad band ultraviolet B (BB-UVB), narrow band ultraviolet B (NB-UVB), oral psoralen plus ultraviolet A (oral PUVA), and topical psoralen plus ultraviolet A (topical PUVA). These treatments are usually delivered at the doctor's office, however the UVB forms may be available for home treatment in the right situation. Outdoor light and tanning beds may be helpful in some patients but are less well controlled.

Systemic treatment, such as pills or injections, can help with more severe cases of psoriasis. When the psoriasis is extensive (greater than 5% of the body surface area) or it effects the person's quality of life (effect on work, social life, marital life, sex life, family life, or psychological well being), and the localized treatments or phototherapy are not an option or haven't worked, systemic treatments are often helpful. Some medicines being used for psoriasis treatment are: methotrexate, acitretin (retinoids), cyclosporine, 6-Thioguanine, hydroxyurea (hydrea), biologic response modifiers and antibiotics. The newest agents, the biologic response modifiers, are injectable proteins that target a specific pathway in the immune system that causes the inflammation in psoriasis. Currently approved by the FDA include Amevive, Enbrel, Raptiva and Remicade. Other agents such as Humira are approved for psoriatic arthritis and awaiting approval from the FDA for psoriasis. These agents are dosed anywhere from two times per week to every other month.

These treatments can be combined with each other to form the best individualized treatment possible.

Consult Your Doctor

If you believe that you or someone you know has psoriasis, please contact your primary care physician or dermatologist. There are also some dermatologists that specifically treat and study psoriasis. Once a full evaluation is performed to assess the psoriasis, it's impact on one's life, and the presence or absence of psoriatic arthritis, there are many treatment options available.

Resources: Questions and Answers about Psoriasis (NIAMS) and the National Psoriasis Foundation.

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This article is a NetWellness exclusive.

Last Reviewed: Jul 30, 2007

Pranav   Sheth, MD Pranav Sheth, MD
Formerly:
College of Medicine
University of Cincinnati