Reference Information about Psoriasis

What is Psoriasis?

Psoriasis can cause discomfort on the inside of the body, as well as the outside.  It can cause embarrassment, anxiety, and pain.  Psoriasis is a chronic autoimmune disorder that can affect the skin, nails, and joints anywhere on the body.  The skin on the scalp, elbows, knees, and lower back are common areas of concern.  On the skin, psoriasis presents itself as silvery-white scales with inflamed red skin underneath.  These plaques are areas where excessive skin cell production has accumulated.  It can be quite painful and may itch, crack, and bleed. Nails affected with psoriasis can appear discolored and look as though they are crumbling.  Pitting of the nails and thickening of the skin under the nails can also be symptoms of this condition.  When joints are affected, the disease is called psoriatic arthritis.  This type of arthritis can affect any joint, but is commonly found in the fingers and toes.  Approximately 10-15% of people who are diagnosed with psoriasis also develop psoriatic arthritis, and suffer from tender, swollen areas of inflammation around the affected joint.  Although there is no cure for this disease, a vast array of treatments and medications are available to psoriasis patients. 

Psoriatic Arthritis

Psoriatic arthritis is a rheumatic condition that can involve the spine, hands, shoulders, elbows, feet, knees, or ankles. It can cause joint damage, inflammation (which sometimes can cause the fingers or toes to appear like sausages), extensive joint stiffness, and pain in the lower back, upper back, and neck.  People with psoriatic arthritis often respond well to medications and treatments that act on the immune system.

What Causes Psoriasis?

Although the cause is not completely understood, there is evidence that psoriasis is an autoimmune disorder, which has hereditary and genetic factors.  Most people with psoriasis have a close family member with the same disorder, although the severity and symptoms may differ for each relative.  Psoriasis is basically a disease of excessive growth and reproduction of skin cells.  In people without psoriasis, the process of manufacturing and shedding skin cells takes approximately twenty-eight days.  For those who have psoriasis, this process happens seven times faster and therefore, cells are not well formed and do not shed from the body as they should.  Instead, the rapid production of skin cells piles up on itself and produces scaly-looking patches of flaky inflamed skin.  The immune system connection is found in the T cells, which help protect the body from infection.  An unnecessary and unexplained activation of these T cells causes them to travel to the dermis and prompt the release of Tumor Necrosis Factor-alpha (TNFa), which results in inflammation and the rapid production of skin cells.  People with immune diseases such as psoriatic arthritis and psoriasis have too much TNF in their bodies.

How is Psoriasis Treated?

There are many treatments available but because of its persistent chronic nature, psoriasis can be a challenge to treat.  Doctors frequently use a trial and error approach to uncover which of the various types of medications is most effective for each patient.  Many factors, including age, overall health, lifestyle, and the severity and location of symptoms can influence the type of treatment prescribed to reduce the inflammation caused by psoriasis and decrease the rate at which new skin cells are produced. Since the course of this disease differs with each individual, doctors must experiment with or combine various treatments to find the most effective therapy for each individual patient.  Topical treatments, oral medications, and biologic drugs have all been found to be effective forms of relief for those who suffer from psoriasis.

Topical Treatments

Treatment of the scalp often begins with over-the-counter (non-prescription) shampoos that have been designed to improve the itch and scaling related to psoriasis.  These shampoos contain tar, salicylic acid, or ketoconazole.  Nizoral® is a shampoo that contains ketoconazole, and Sebulex® is a shampoo with 2% salicylic acid. Both products may be effective in the reduction of the dandruff-like flakes which occur as part of scalp psoriasis.  Psoriasis that affects the body can be treated with an over-the-counter cream containing ketoconazole, called Xolegel®.

When over-the-counter products prove not to be effective in reducing the symptoms of psoriasis, doctors will prescribe topical creams, gels, ointments, shampoos, or scalp lotions containing corticosteroids, calcipotriol, or tazarotene.

Clobex® Spray, Celestoderm® Cream, Diprolene® Lotion, and Taclonex® Ointment are topical corticosteroids.  They are the most commonly prescribed psoriasis medications.  These can all be applied directly to the psoriasis plaques and can help to reduce inflammation, remove built-up scales, and reduce skin turn over.

Dovonex® is a topical calcipotriol that is available in many forms and is derived from vitamin D.  It affects cells in the epidermis called keratinocytes, which produce keratin (the main structural protein of the skin).  Dovonex is known to slow down the turn over of epidermal cells by manipulating keratinocyte differentiation.

Tazorac® is a topical tazarotene that is available as a cream and a gel. It is a selective retinoid with properties that are similar to vitamin A.  It works by inducing growth suppressor genes in keratinocytes. 

Oral Treatment

If the treatment goal is not achieved with topical corticosteroids, tazarotene, or calcipotriol, then therapies with greater effectiveness (and greater toxicity) can be used by psoriasis patients.  Medications which are taken internally by pill or injection are the next step in the treatment plan.

Metotrexate is a folic acid derivative that acts specifically during DNA and RNA synthesis.  This medication is known as a disease modifying anti-rheumatic drug (DMARD) and is a cytotoxic agent (a chemical that is directly toxic to cells) with a specific toxic effect on rapidly dividing cells.  It has multiple characteristics, and can also be described as an immunosuppressant.  Methotrexate is an effective treatment for psoriasis and psoriatic arthritis because of its effect on cellular replication.

Soriatane® (Acitretin) is a retinoid (a vitamin A related compound that promotes DNA transcription).  It has properties similar to vitamin A.  It is taken once a day orally and used to help relieve and control severe psoriasis.  It is particularly effective for pustular psoriasis. Soriatane inhibits cell replication by adjusting cellular differentiation within the epidermis.  In other words, it slows down the rapid growth rate of skin cells and helps to reduce the psoriasis activity.

Neoral® (Cyclosporin) is an immunosuppressive agent used in the treatment of psoriasis, as well as organ transplantation.  It is very effective, but often used only for people with severe, disabling, resistant psoriasis.

Biologic Drugs

Most recently introduced as a treatment of psoriasis are the biologics.  These drugs are designed specifically to hit immunological targets that are involved in specific conditions.  Other immune therapies have had a general suppressing effect on the immune system which prevented high doses from being used because of the fear of side effects.  With new biologic drugs such as, Enbrel® and Humira®, available to psoriasis patients, more specific targets can be blocked and less interference with other biological functions is experienced, meaning fewer side effects.

Enbrel® (Etanercept) is a TNF receptor fused onto human IgG (the most abundant form of antibody in the blood).  It is known as an immune response modifier and has shown excellent results against psoriatic arthritis and severe psoriasis. Enbrel® can block the damage that too much TNF can cause.  It works by inhibiting TNF activity in the body, thereby slowing down the production of skin cells.  It is a protein and is injected just under the skin.  Enbrel® injections can be self-administered at home.