Editing Psoriasis (section)

====Severity====
[[Image:Distribution of psoriasis severity.svg|thumb|Distribution of severity]]
No consensus exists about how to classify the severity of psoriasis. Mild psoriasis has been defined as a percentage of body surface area (BSA)≤10, a [[Psoriasis Area and Severity Index]] (PASI) score ≤10, and a [[Dermatology Life Quality Index]] (DLQI) score ≤10.<ref name="Mrowietz2011">{{cite journal | vauthors = Mrowietz U, Kragballe K, Reich K, Spuls P, Griffiths CE, Nast A, Franke J, Antoniou C, Arenberger P, Balieva F, Bylaite M, Correia O, Daudén E, Gisondi P, Iversen L, Kemény L, Lahfa M, Nijsten T, Rantanen T, Reich A, Rosenbach T, Segaert S, Smith C, Talme T, Volc-Platzer B, Yawalkar N | title = Definition of treatment goals for moderate to severe psoriasis: a European consensus | journal = Archives of Dermatological Research | volume = 303 | issue = 1 | pages = 1–10 | date = January 2011 | pmid = 20857129 | pmc = 3016217 | doi = 10.1007/s00403-010-1080-1 }}</ref> Moderate to severe psoriasis was defined by the same group as BSA >10 or PASI score >10 and a DLQI score >10.<ref name="Mrowietz2011"/>

The DLQI is a 10-question tool used to measure the impact of several dermatologic diseases on daily functioning. The DLQI score ranges from 0 (minimal impairment) to 30 (maximal impairment) and is calculated with each answer being assigned 0–3 points with higher scores indicating greater social or occupational impairment.<ref name="Mease2011">{{cite journal | vauthors = Mease PJ | title = Measures of psoriatic arthritis: Tender and Swollen Joint Assessment, Psoriasis Area and Severity Index (PASI), Nail Psoriasis Severity Index (NAPSI), Modified Nail Psoriasis Severity Index (mNAPSI), Mander/Newcastle Enthesitis Index (MEI), Leeds Enthesitis Index (LEI), Spondyloarthritis Research Consortium of Canada (SPARCC), Maastricht Ankylosing Spondylitis Enthesis Score (MASES), Leeds Dactylitis Index (LDI), Patient Global for Psoriatic Arthritis, Dermatology Life Quality Index (DLQI), Psoriatic Arthritis Quality of Life (PsAQOL), Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F), Psoriatic Arthritis Response Criteria (PsARC), Psoriatic Arthritis Joint Activity Index (PsAJAI), Disease Activity in Psoriatic Arthritis (DAPSA), and Composite Psoriatic Disease Activity Index (CPDAI) | journal = Arthritis Care & Research | volume = 63 | issue = Supplement 11 | pages = S64–85 | date = November 2011 | pmid = 22588772 | doi = 10.1002/acr.20577 }}</ref>

The PASI is the most widely used measurement tool for psoriasis. It assesses the severity of lesions and the area affected and combines these two factors into a single score from 0 (no disease) to 72 (maximal disease).<ref>{{cite journal|url=http://www.skinandaging.com/article/5394|archive-url=https://web.archive.org/web/20110302031858/http://www.skinandaging.com/article/5394|url-status=dead|archive-date=2 March 2011|title=Psoriasis Update |journal=Skin & Aging |volume=14 |issue=3|year=2006 |pages=46–50}}</ref> Nevertheless, the PASI can be too unwieldy to use outside of research settings, which has led to attempts to simplify the index for clinical use.<ref name="pmid15530297">{{cite journal | vauthors = Louden BA, Pearce DJ, Lang W, Feldman SR | title = A Simplified Psoriasis Area Severity Index (SPASI) for rating psoriasis severity in clinic patients | journal = Dermatology Online Journal | volume = 10 | issue = 2 | pages = 7 | date = October 2004 | doi = 10.5070/D318W9J736 | pmid = 15530297 }}</ref>