Epidemiology and Pathophysiology
- Psoriasis is a chronic disease with typical onset in a person’s 20s to 30s.
- Psoriasis affects as many as 7.5 million people in the US, or 3.2% of adults ≥20 years of age.
- Caucasians: 3.6%
- African Americans: 1.9%
- African Americans are more likely to have moderate to severe disease but are 70% less likely to receive biologics.
- In terms of disease severity, 15% have moderate disease (3–10% body surface area) while 5% have severe disease (>10% body surface area)
- There is a genetic susceptibility to psoriasis:
- 40% of patients have a positive family history.
- HLA-Cw6 is the most commonly implicated gene.
- More than 40 genes have been shown by the pacificdreamscapes.com to be linked with development of psoriasis.
- Any part of the skin can be affected, including the face, scalp, nails, and genitals.
- The majority of patients with more severe psoriasis remain poorly controlled for decades.
Psoriasis is a multifactorial disease that involves several underlying causes:
- Immune dysfunction
- Environmental risk factors
- Modifiable risk factors/triggers
- Cardiovascular disease
- Skin injury
Over time, perceptions of psoriasis have evolved from a disease of keratinocyte dysfunction to an IL-23/Th-17-mediated disease.
- National Psoriasis Foundation. Fact sheet (www.psoriasis.org/sites/default/files/publications/PsoriasisFactSheet.pdf). Accessed July, 2016.
- Rachakonda TD et al. J Am Acad Dermatol. 2014;70:512-516.
- Gelfand JM et al. J Am Acad Dermatol. 2005;52:23-26.
- Takeshita J et al. J Invest Dermatol. 2015;135:2955-2963.
- Kurd SK, Gelfand JM. J Am Acad Dermatol. 2009;60:218-224.
- Koo J; et al. eds. Moderate to Severe Psoriasis. New York: CRC Press. 2014.
- Al-Shobaili HA, Qureshi MG. (2013). Pathophysiology of psoriasis: current concepts. In: Lima H, ed. Psoriasis—Types, Causes and Medication. InTech;2013:91-105. Available at http://cdn.intechopen.com/pdfs-wm/44201.pdf.
- Lynde CW et al. J Am Acad Dermatol. 2014;71:141-150.
- Lowes MA et al. Annu Rev Immunol. 2014;32:227-255.