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Source: Law RM, Gulliver WP. Psoriasis. In: DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey LM, eds. Pharmacotherapy: A Pathophysiologic Approach. 10th ed. New York, NY: McGraw-Hill; 2017. http://accesspharmacy.mhmedical.com/content.aspx?bookid=1861§ionid=146069987. Accessed March 28, 2017.
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Receptors on T lymphocytes interact with antigens on surface of antigen-presenting dendritic cells and macrophages.
Activated T cells migrate into skin and secrete cytokines (eg, interferon-γ and interleukin 2 [IL-2]) that induce pathologic skin changes.
Genetic component may involve human leukocyte antigens (HLA) Cw6, TNF-α, and IL-3.
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Affects about 2% of population in the United States and Europe.
Worldwide prevalence varies between 0.1% and 3%, with variations due to racial, geographic, and environmental differences.
Affects males and females equally; onset usually before age of 40.
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CLINICAL PRESENTATION
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Well-demarcated, erythematous, red-violet skin lesions at least 0.5 cm in diameter; typically covered with silver flaking scales.
May be single lesions at predisposed areas (eg, knees and elbows) or generalized over wide body surface area (BSA).
Pruritus may be severe and require treatment to minimize excoriations from frequent scratching.
Psoriatic arthritis involves both psoriatic lesions and inflammatory, arthritis-like symptoms.
Distal interphalangeal joints and adjacent nails most commonly involved, but knees, elbows, wrists, and ankles may also be affected.
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MEANS OF CONFIRMATION AND DIAGNOSIS
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Characteristic skin lesions on physical examination.
Classification as mild, moderate, or severe based on BSA affected and Psoriasis Area and Severity Index (PASI) measurements.
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DIAGNOSTIC PROCEDURES
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DIFFERENTIAL DIAGNOSIS
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Minimize or eliminate skin lesions.
Alleviate pruritus.
Reduce frequency of flare-ups.
Avoid adverse treatment effects.
Provide appropriate counseling (eg, stress reduction).
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TREATMENT: GENERAL APPROACH
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