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[Gr. psōriasis, itching]
A chronic skin disorder in which red papules and scaly silvery plaques with sharply defined borders appear on the body surface.
psoriatic (sōr″ē-at′ik)
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, adj.
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PSORIASIS Silvery plaque on the shin
Although psoriasis may begin at any time of life, the most common age of onset is between 10 and 40. Sudden onset may be related to HIV. The condition has relapses and partial remissions, but established lesions often persist for many months or years. Flare-ups may be related to specific systemic and environmental factors or may be unpredictable. About 5% of patients also develop inflammatory arthritis that commonly affects fingers and toes or sacroiliac joints, and patients with psoriasis have an increased rate of inflammatory bowel disease.

Psoriasis affects approx. 1% to 2% of the population.

Although the cause of psoriasis is unknown, some evidence suggests that immune dysregulation contributes to excessive proliferation of skin. Families with psoriasis have been found to have a significantly higher than normal incidence of certain human leukocyte antigens. Genetic studies show that about one third of affected patients have a family history of the disease. Emotional stress, skin trauma, cold weather, infections, and some drugs may trigger attacks.

The rash is commonly found on the knees, shins, elbows, umbilicus, lower back, buttocks, ears, and along the hairline. Pitting of the nails also occurs frequently. Patients complain of itching and sometimes of pain from dry, cracked, or encrusted lesions. Removal of scales usually causes fine bleeding points. Widespread shedding of scales is common, and occasionally the disease becomes pustular. The severity of the disease may range from a minimal cosmetic problem to total body surface involvement. About a third of all affected patients have a family history of the disease.

There are no specific blood tests or diagnostic procedures for psoriasis; diagnosis is usually based on the appearance of the skin. A skin biopsy or scraping may occasionally be needed to rule out other disorders.

There is no cure for psoriasis, and all treatments are palliative. Topical corticosteroids, coal tar derivatives, vitamin D3 analogs (such as calcipotriene), retinoids (such as etretinate, tacarotene), ultraviolet light exposure, and saltwater immersion are among the many methods that have been used effectively to treat psoriasis. For severe disease, exposure to ultraviolet light, or immune-modulating drugs like methotrexate, cyclosporine or monoclonal biologic agents are sometimes used, with close monitoring to prevent side effects.

Obesity is associated with psoriasis, and weight loss improves the rash. Bariatric surgery, which leads to significant weight loss, improves psoriasis in most patients.

Descriptive text is not available for this imageMany treatments for psoriasis carry some risk for the patient. Etretinate, for example, produces fetal abnormalities and should never be used by women of childbearing age. Phototherapy with ultraviolet light increases the risk of developing many types of skin cancer. Patients receiving psoralen + ultraviolet A (PUVA) therapy must wear goggles during treatments, stay out of the sun on treatment days, and protect their eyes with ultraviolet A-(UVA)-screening sunglasses for 24 hr after the therapy. Use of methotrexate use requires regular monitoring of liver function, renal function, complete blood counts, and lung function.

Patients with psoriasis have, in addition to skin disease, an increased risk of other health problems, including arthritis, chronic kidney disease, chronic obstructive pulmonary disease, diabetes mellitus, heart attack, peptic ulcers, and peripheral vascular disease.

The nurse teaches the patient the prescribed therapy to soften and remove scales, to relieve pruritus, to reduce pain and discomfort, to retard rapid cell proliferation, and to help induce remission and monitor adverse reactions. Assistance is provided to help the patient gain confidence in managing these largely palliative treatments, many of which require special instructions for application and removal. The patient should protect against and minimize trauma. The patient's ability to manage therapies is evaluated. The patient learns to identify stressors that exacerbate the condition and to avoid or reduce these as much as possible. If the patient smokes cigarettes, participation in a smoking cessation program is recommended. The nurse helps the young patient (aged 20 to 30) to deal with body image changes and effects on self-esteem, encourages the patient to verbalize feelings, and supports the patient through loss of body image and associated grief. Psychological problems often occur. Referral for psychological counseling or cosmetic concealment therapy may be necessary. Patients and their families should be referred to the National Psoriasis Foundation and its local chapters for information and support. (800-723-9166;

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