Editing Psoriasis (section)

===Nail changes===
[[File:Luszczyca paznokcia.jpg|thumbnail|Psoriasis of a fingernail, with visible pitting]]
[[File:NailPsoriasis.JPG|thumb|Effect of psoriasis on the toenails]]
[[Psoriatic nails|Psoriasis can affect the nails]] and produces a variety of changes in the appearance of fingers and toenails. Nail psoriasis occurs in 40–45% of people with psoriasis affecting the skin, and has a lifetime incidence of 80–90% in those with psoriatic arthritis.<ref name="Tan2012">{{cite journal | vauthors = Tan ES, Chong WS, Tey HL | title = Nail psoriasis: a review | journal = American Journal of Clinical Dermatology | volume = 13 | issue = 6 | pages = 375–88 | date = December 2012 | pmid = 22784035 | doi = 10.2165/11597000-000000000-00000 | s2cid = 8561015 }}</ref> These changes include pitting of the nails (pinhead-sized depressions in the nail is seen in 70% with nail psoriasis), [[leukonychia|whitening of the nail]], [[splinter hemorrhage|small areas of bleeding from capillaries under the nail]], yellow-reddish discoloration of the nails known as the oil drop or salmon spots, dryness, thickening of the skin under the nail (subungual hyperkeratosis), loosening and separation of the nail ([[onycholysis]]), and crumbling of the nail.<ref name="Tan2012"/>