Editing Psoriasis (section)

==Epidemiology==
Psoriasis is estimated to affect 2–4% of the population of the western world.<ref name="Parisi2013" /> The rate of psoriasis varies according to age, region and ethnicity; a combination of environmental and genetic factors is thought to be responsible for these differences.<ref name=Parisi2013/> Psoriasis is about five times more common in people of European descent than in people of Asian descent,<ref>{{cite web |title=Psoriasis affects more than 8 million people in the U.S. |url=https://www.psoriasis.org/advance/why-psoriasis-less-common-asians |access-date=12 July 2021 |publisher=National Psoriasis Foundation |archive-date=24 February 2024 |archive-url=https://web.archive.org/web/20240224040820/https://www.psoriasis.org/about-psoriasis/ |url-status=live }}</ref> more common in countries farther from the [[equator]],<ref name="Guerra2013" /> relatively uncommon in African Americans, and extremely uncommon in Native Americans.<ref name="Weller2008" /> Psoriasis has been estimated to affect about 6.7{{Spaces}}million Americans.<ref name="NIH2015" />

Psoriasis can occur at any age, although it is more frequent in adults and commonly appears for the first time between the ages of 15 and 25 years.<ref name="NIH2015" /> Approximately one-third of people with psoriasis report being diagnosed before age 20.<ref>{{cite journal | vauthors = Benoit S, Hamm H | title = Childhood psoriasis | journal = Clinics in Dermatology | volume = 25 | issue = 6 | pages = 555–62 | year = 2007 | pmid = 18021892 | doi = 10.1016/j.clindermatol.2007.08.009 }}</ref> Psoriasis affects both [[sex]]es equally.<ref name="Kupetsky2013">{{cite journal | vauthors = Kupetsky EA, Keller M | title = Psoriasis vulgaris: an evidence-based guide for primary care | journal = Journal of the American Board of Family Medicine | volume = 26 | issue = 6 | pages = 787–801 | date = November–December 2013 | pmid = 24204077 | doi = 10.3122/jabfm.2013.06.130055 | doi-access = free | title-link = doi }}</ref>

People with [[inflammatory bowel disease]] such as Crohn's disease or ulcerative colitis are at an increased risk of developing psoriasis.<ref name="Guerra2013" />