Editing Crohn's disease (section)

====Dermatological====
[[File:A single EN.JPG|thumb|A single lesion of erythema nodosum]]

Crohn's disease may also involve the skin, blood, and [[endocrine system]]. [[Erythema nodosum]] is the most common type of skin problem, occurring in around 8% of people with Crohn's disease, producing raised, tender red [[Nodule (medicine)|nodule]]s usually appearing on the [[Tibia|shin]]s.<ref name="Trikudanathan2012">{{cite journal | vauthors = Trikudanathan G, Venkatesh PG, Navaneethan U | title = Diagnosis and therapeutic management of extra-intestinal manifestations of inflammatory bowel disease | journal = Drugs | volume = 72 | issue = 18 | pages = 2333–2349 | date = December 2012 | pmid = 23181971 | doi = 10.2165/11638120-000000000-00000 | s2cid = 10078879 }}</ref><ref name="Thrash2013">{{cite journal | vauthors = Thrash B, Patel M, Shah KR, Boland CR, Menter A | title = Cutaneous manifestations of gastrointestinal disease: part II | journal = Journal of the American Academy of Dermatology | volume = 68 | issue = 2 | pages = 211.e1-33; quiz 244–6 | date = February 2013 | pmid = 23317981 | doi = 10.1016/j.jaad.2012.10.036 | s2cid = 1819416 }}</ref><ref name="PMID30682031">{{cite journal | vauthors = Roth N, Biedermann L, Fournier N, Butter M, Vavricka SR, Navarini AA, Rogler G, Scharl M | title = Occurrence of skin manifestations in patients of the Swiss Inflammatory Bowel Disease Cohort Study | journal = PLOS ONE | volume = 14 | issue = 1 | pages = e0210436 | date = 2019 | pmid = 30682031 | pmc = 6347222 | doi = 10.1371/journal.pone.0210436 | s2cid = 59275029 | doi-access = free | title-link = doi | bibcode = 2019PLoSO..1410436R }}</ref> Erythema nodosum is due to inflammation of the underlying [[subcutaneous tissue]], and is characterized by [[septal]] [[panniculitis]].<ref name="Thrash2013" />

[[Pyoderma gangrenosum]] is a less common skin problem, occurring in under 2%,<ref name="PMID30682031" /> and is typically a painful ulcerating nodule.<ref name="Thrash2013" /><ref name="Harbord" />

[[Nail clubbing|Clubbing]], a deformity of the ends of the fingers, may also be a result of Crohn's disease.<ref>{{cite journal | vauthors = Kitis G, Thompson H, Allan RN | title = Finger clubbing in inflammatory bowel disease: its prevalence and pathogenesis | journal = British Medical Journal | volume = 2 | issue = 6194 | pages = 825–828 | date = October 1979 | pmid = 509114 | pmc = 1596648 | doi = 10.1136/bmj.2.6194.825 }}</ref><ref>{{cite journal | vauthors = Kapsoritakis AN, Psychos AK, Sfiridaki A, Zintzaras E, Potamianos SP | title = Finger clubbing and erythropoietin serum levels in active IBD | journal = Inflammatory Bowel Diseases | volume = 12 | issue = 6 | pages = 535–536 | date = June 2006 | pmid = 16775499 | doi = 10.1097/00054725-200606000-00014 }}</ref>

Other very rare dermatological manifestations include: [[pyostomatitis vegetans]], [[erythema multiforme]], [[Epidermolysis bullosa acquisita|epidermolysis bullosa acquista]] (described in a case report), and metastatic Crohn's disease (the spread of Crohn's inflammation to the skin<ref name="Cutaneous" />).<ref name="Manifestations" /> It is unknown if [[Sweet's syndrome]] is connected to Crohn's disease.<ref name="Manifestations" />