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Psoriasis - Risk Factors

Description

An in-depth report on the causes, diagnosis, treatment, and prevention of psoriasis.

Diagnosis:

A microscopic examination of tissue taken from the affected skin patch is needed to make a definitive diagnosis of psoriasis and to distinguish it from other skin disorders. Usually in psoriasis, the examination will show a large number of dry skin cells, but without many signs of inflammation or infection. Specific changes in the nails are often strong signs of psoriasis.

Disease Severity

The severity of psoriasis ranges from one or two flaky inflamed patches to widespread pustular psoriasis that, in rare cases, can be life threatening. To help determine the best treatment for a patient, doctors usually classify the disease as mild to severe. The classification depends on how much of the skin is affected:

Mild psoriasis affects less than 3% of the body surface. Most cases of psoriasis are limited to less than 2% of the skin.
Moderate psoriasis covers 3 - 10% of the skin.
If more than 10% of the body is affected, the disease is considered severe.

The palm of the hand equals 1% of the body.

The severity of the disease is also measured by its effect on a person's quality of life.

The National Psoriasis Foundation has proposed a new classification method. The group suggests a two-tiered system that classifies patients as needing either local or body-wide (systemic) treatment.

Although disease severity impacts treatment success, some forms of psoriasis can be very resistant to treatment, even though they are not categorized as severe. They include:

Any psoriasis on the palms and soles (hand and foot psoriasis)
Inverse psoriasis (which occurs in the folds of the skin)
Scalp psoriasis
Psoriatic arthritis

Resources

www.psoriasis.org -- National Psoriasis Foundation
www.aad.org -- American Academy of Dermatology
www.niams.nih.gov -- National Institute of Arthritis and Musculoskeletal and Skin Diseases
www.clinicaltrials.gov -- Find clinical trials

References

Chen YJ, Wu CY, Shen JL, Chu SY, Chen CK, Chang YT, Chen CM. Psoriasis independently associated with hyperleptinemia contributing to metabolic syndrome. Arch Derm. 2008;144:1571-1575.

Gelfand JM, Neimann AL, Shin DB, et al. Risk of myocardial infarction in patients with psoriasis. JAMA. 2006 Oct 11;296(14):1735-41.

Kurd SK, Gelfand JM. The prevalence of previously diagnosed and undiagnosed psoriasis in US adults: Results from NHANES 2003-2004. J Am Acad Dermatol. 2008 [Epub ahead of print].

Leonardi CL, Kimball AB, Papp KA, Yeilding N, Guzzo C, Wang Y, et al. Efficacy and safety of ustekinumab, a human interleukin-12/23 monoclonal antibody, in patients with psoriasis: 76-week results from a randomized, double-blind, placebo-controlled trial (PHOENIX 1). Lancet. 2008;371:1665-1674.

Liu Y, Helms C, Liao W, Zaba LC, Duan S, Gardner J, et al. A genome-wide association study of psoriasis and psoriatic arthritis identifies new disease loci. PLoS Genet. 2008;4(3):e1000041.

Menter A, Gottlieb A, Feldman SR, Voorhees ASV, Leonardi CL, Gordon KB, et al. Guidelines for the management of psoriasis and psoriatic arthritis. J Am Acad Dermatol. 2008;5:826-850.

Menter A, Griffiths CE. Current and future management of psoriasis. Lancet. 2007;370:272-284.

Paller AS, Siegfried EC, Langley RG, Gottlieb AB, Pariser D, Landells I, et al. Etanercept treatment for children and adolescents with plaque psoriasis. N Engl J Med. 2008;358:241-251.

Papp K, Bissonnette R, Rosoph L, Wasel N, Lynde CW, Searles G, et al. Efficacy of ISA247 in plaque psoriasis: a randomized multicentre, double-blind, placebo-controlled phase III study. Lancet. 2008;371:1337-1342.

Stern RS. Psoralen and ultraviolet A light therapy for psoriasis. N Engl J Med. 2007;357:682-690.

U.S. Food and Drug Administration. CDER Drug and Biologic Approvals for Calendar Year 2006 -- Updated through August 31, 2006. Last accessed on 15 October, 2006.

Weatherhead S, Robson SC, Reynolds NJ. Management of psoriasis in pregnancy. BMJ. 2007;334:1218-1220.

Reviewed last on: 4/10/2009
A.D.A.M. Editorial Team: David Zieve, MD, MHA, Greg Juhn, MTPW, David R. Eltz. Previously reviewed by Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School (1/13/2009).

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