by Cheryl Jones

Created on: April 25, 2009

What is Psoriasis

Psoriasis is a lifelong condition affecting the skin or joints. The exact cause is unknown, but it tends to run in families. It is believed to be an autoimmune disease; that is, a person's immune system becomes overly aggressive.

Several subtypes of psoriasis exist, but all types cause distinct red crusty patches on the skin. Normally, new skin cells are produced deep in the epidermis. As the new cells mature, they migrate to the surface where they die and are sloughed off. The process takes 30 days. In people with psoriasis, however, this cycle is accelerated and new skin cells are produced and mature every 3 to 4 days. The excess dead cells fail to slough off and instead create scaly lesions. Psoriasis may affect the joints after the skin. This is called psoriatic arthritis and typically occurs in finger and toe joints first.

Diagnosis

Psoriasis diagnosis is difficult, especially in the early stages. In early, mild cases, symptoms such as rash and dandruff are easily overlooked or misinterpreted as an infection or allergic reaction. No definitive blood or lab test exists to diagnose psoriasis. Diagnosis is made by examining the characteristic skin lesions and fingernails. Fingernail pitting is a distinct early sign of psoriasis. The diagnosis is confirmed by viewing a sample of the skin lesions under a microscope. Psoriatic cells are thick, red and flaky. Psoriatic arthritis typically begins in fingers and toes, but may occur in other joints in no particular pattern. Psoriatic arthritis cannot be diagnosed by a blood test, but a blood test will identify rheumatoid arthritis and distinguish between the psoriatic and rheumatoid arthritis.

Treatment

There is no cure for psoriasis. People with psoriasis will experience periodic outbreaks brought on by stress, allergy, illness, weather changes, minor injuries, certain medications or streptococcal or human immunodeficiency virus (HIV) infection.

Treatment depends largely on the severity of the outbreak, although each person will react differently. For mild psoriasis outbreaks, topical corticosteroid creams and ointments are effective. Phototherapy, which is treatment with ultraviolet (UV) B light and excimer lasers, is also effective in clearing skin lesions. More severe outbreaks may require medications such as methotrexate, cyclosporin A or anti-TNF (tumor necrosis factor) inhibitors. Anti-TNF inhibitors, such as etanercept (Enbrel) and infliximab (Remicade), effectively control skin and arthritic psoriasis, but these medications require regular injections. They are also associated with side effects including tuberculosis and other infections.

Keep skin moisturized to control the itching that accompanies psoriasis outbreaks, and use cold compresses, cool showers, antihistamines, topical corticosteroids and antihistamines to ease the discomfort.

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