Psoriasis

Definition

Psoriasis is a common skin inflammation (irritation and swelling) characterized by frequent episodes of redness, itching, and thick, dry, silvery scales on the skin.

Alternative Names

Plaque psoriasis

Causes, incidence, and risk factors

Psoriasis is a very common condition, with approximately 5 million Americans affected. It can appear suddenly or gradually. In many cases, psoriasis goes away and then flares up again repeatedly over time. The disorder may affect people of any age, but it most commonly begins between ages 15 and 35.

Psoriasis seems to be an inherited disorder, probably related to an inflammatory response in which the immune system accidentally targets the body's own cells. Evidence of the condition is most commonly seen on the trunk, elbows, knees, scalp, nails, trunk, or less commonly, skin folds, but it may affect any or all parts of the skin.

Normally, it takes about a month for new skin cells to move up from the lower layers to the surface. In psoriasis, this process takes only a few days, resulting in a build-up of dead skin cells and formation of thick scales.

Psoriasis may be aggravated by injury or irritation (such as cuts, burns, rashes, insect bites). It may be severe in immunosuppressed people (like those with AIDS or undergoing chemotherapy for cancer), or those who have other autoimmune disorders (such as rheumatoid arthritis). Up to 30% of people with psoriasis may also have arthritis, a condition known as psoriatic arthritis.

Some medications (notably beta blockers and lithium), viral or bacterial infections (most commonly strep), excessive alcohol consumption, friction, sunburn, conditions of dryness or low sunlight such as occur in the winter, and stress can also cause psoriasis flare-ups or make psoriasis more difficult to treat. The condition is not contagious.

Infections with strep may cause the sudden appearance of numerous, small lesions of psoriasis, in a pattern that resembles raindrops. This condition is called guttate psoriasis from the Latin word for rain. This is more common in children and young adults. Guttate psoriasis is short-lived and can disappear without treatment.

The nails may also be affected by psoriasis. It is estimated that 10% of people with psoriasis have visible changes only in the nails. Nail changes include yellow-brown spots under the nail ("oil spots"), pitting (pinpoint depressions on the nail surface), separation of the nail from the base at the furthest edge, and thickening that can mimic fungal infection of the nails.

Symptoms

• Skin patches
  • Pink-red (so-called "salmon-colored")
  • Usually dry and covered with silvery scales
  • Raised
  • Usually individual with sharp borders
  • Most often located on the elbows, knees, and trunk
  • o Coarse scaling of the scalp
• Nail changes
• Small scaling pink-red dots on the skin (especially in children and young adults)
• Joint pain or aching, which may be a special type of arthritis (psoriatic arthritis)

Additional symptoms that may be associated with this disease:

• Nail abnormalities
• Genital lesions in males

Signs and tests

The diagnosis is usually based on the appearance of the skin.

• A skin biopsy may be needed to rule out other disorders.
• An x-ray may be used to check for psoriatic arthritis if joint pain is present and persistent.

Treatment

Treatment is focused on control of the symptoms and prevention of secondary infections. It varies with the extent and severity of the disorder. Severe or resistant cases may require intensive treatment.

Psoriasis that covers all or most of the body is an emergency that requires hospitalization. The disorder is very rare. It may be painful. The body loses vast quantities of fluid and is susceptible to severe secondary infections that can become systemic, involve internal organs and even progress to septic shock and death. Treatment includes analgesics, sedation, intravenous fluids, and antibiotics.

Mild cases are usually treated at home. Topical medications (applied to the skin) include:

• Corticosteroid creams or ointments
• Prescription creams or ointments containing substances that are related to vitamin D (calcipotriol) or vitamin A (retinoids)
• Prescription or nonprescription dandruff shampoos
• Shampoos or ointments that contain coal tar
• Ointments or creams that contain anthralin
• Moisturizers
• Creams to remove the scaling (usually salicylic acid or lactic acid)
• Antibiotics, where infection with strep is suspected

Oral medications, such as retinoids or drugs that suppress inflammation (immunosuppressants such as methotrexate or cyclosporine), may be given. These are usually prescribed in more severe cases, when a large amount of body surface area is affected, or when topical treatment has not succeeded. They are also prescribed when the psoriasis is accompanied by arthritis. Women of childbearing age may not be treated with some of these medications.Other treatments may include short, controlled exposures to ultraviolet light (phototherapy). In some cases, the skin is first sensitized (made sensitive) to the ultraviolet light by the application of coal tar ointment, or by taking oral psoralens (special medicine with plant material in it). These treatments are performed in a lightbox in the doctor's office and usually require 2 to 3 visits per week.

For patients with severe disease, a newer option is treatment with medicines referred to as biologics.These are proteins and therefore must be injected rather than taken orally. They target the cause of psoriasis by interfering with the body's inflammatory response. Alefacept (Amevive), efalizumab (Raptiva), etanercept (Enbrel), and infliximab (Remicade) are FDA-approved for treatment of psoriasis. Adalimumab (Humira) is approved by the FDA for the treatment of psoriatic arthritis, but not as yet for psoriasis alone. These medications are very expensive, however, and like all medications they may have side effects. They are therefore not used as first-line therapy but can be used when other treatments have not worked.

Maintain good general health to reduce the risk of flare-ups. Obtain adequate rest and exercise, eat a well-balanced diet and avoid stress (see stress management). Treat strep throat and other infections promptly.

Maintain good skin hygiene to prevent secondary infections. Daily baths or showers are recommended. Avoid harsh scrubbing, which can irritate the skin and cause new outbreaks.

Oatmeal baths may be soothing and may help to loosen scales. Commercial preparations may be used, or mix one cup of oatmeal into a tub of warm water.

Support Groups

If having psoriasis is causing significant stress, consider joining a psoriasis support group with members who share common experiences and problems.

Expectations (prognosis)

Psoriasis is a chronic, lifelong condition that can be controlled with treatment. It can clear for extended periods and relapse. It usually does not adversely affect general health, unless it is neglected.

Complications

• Complications that result from the treatment itself
• Secondary skin infections

Calling your health care provider

Call for an appointment with your health care provider if symptoms indicate psoriasis. Call for an appointment if psoriasis recurs frequently despite treatment. Let your provider know if your psoriasis seems to be accompanied by joint pain or fever.

Go to the emergency room or call the local emergency number (such as 911) if there is a severe outbreak which covers all or most of the body.

Also, seek medical attention if pustules, fever, muscle aches, fatigue or other new or unexplained symptoms develop.

Prevention

No form of prevention is known. Well-moisturized skin may be less prone to psoriasis. Keep flare-ups to a minimum by avoiding anything that aggravates your psoriasis.

•	Itching
•	Scales
•	Immune response
•	Immunodeficiency disorders...
•	Autoimmune disorders
•	Rheumatoid arthritis
•	Stress and anxiety