Editing Malar rash

{{short description|Red, scaly rash of the cheeks and bridge of the nose}}
{{More citations needed|article|date=December 2020}}
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| caption         = A malar rash, or "butterfly rash", is characteristically red or purplish and mildly scaly (seen in patients with systemic lupus erythematosus).
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A '''malar rash''' ({{ety|la|mala|jaw, cheek-bone}}), also called '''butterfly rash''',<ref name=":0">{{cite book | vauthors = Nouh A, Speiser J, Biller J | chapter = Chapter 3 - Acquired neurocutaneous disorders|date=2015-01-01 | title = Handbook of Clinical Neurology|volume=132|pages=29–73| veditors = Islam MP, Roach ES |series=Neurocutaneous Syndromes |publisher=Elsevier |doi=10.1016/b978-0-444-62702-5.00003-2 | pmid = 26564070| isbn = 9780444627025}}</ref> is a [[medical sign]] consisting of a characteristic form of facial [[rash]]. It is often seen in [[lupus erythematosus]]. More rarely, it is also seen in other diseases, such as [[pellagra]], [[dermatomyositis]], and [[Bloom syndrome]].

Many conditions can cause rashes with a similar appearance to a malar rash.<ref name=":0" /> A malar rash is present in approximately 46–65% of people with lupus.

== Definition ==
A malar rash of lupus is red or purplish and mildly scaly. It has the characteristic shape of a butterfly, and involves the bridge of the nose. Notably, the rash spares the [[nasolabial folds]] of the face, which contributes to its characteristic appearance. It is usually macular with sharp edges, and not itchy. The rash can be transient or progressive with involvement of other parts of the facial skin.{{citation needed|date=August 2015}}

While some literature has described the slapped-cheek rash of [[fifth disease]] as a malar rash, it differs slightly in that the nose is typically spared.<ref>{{cite journal | vauthors = Cooray M, Manolakos JJ, Wright DS, Haider S, Patel A | title = Parvovirus infection mimicking systemic lupus erythematosus | journal = CMAJ | volume = 185 | issue = 15 | pages = 1342–4 | date = October 2013 | pmid = 23979870 | pmc = 3796600 | doi = 10.1503/cmaj.121565}}</ref>

== Differential diagnosis ==
Conditions that can cause rashes with a similar appearance to a malar rash include:

* [[lupus erythematosus]]<ref name=":1">{{cite journal | vauthors = Uva L, Miguel D, Pinheiro C, Freitas JP, Marques Gomes M, Filipe P | title = Cutaneous manifestations of systemic lupus erythematosus. | journal = Autoimmune Diseases | date = October 2012 | volume = 2012 | page = 834291 | doi = 10.1155/2012/834291 | pmid = 22888407 | pmc = 3410306 | doi-access = free }}</ref>
* [[pellagra]]<ref>{{cite journal | vauthors = Dreizen S | title = The butterfly rash and the malar flush. What diseases do these signs reflect? | journal = Postgraduate Medicine | volume = 89 | issue = 1 | pages = 225–8, 233–4 | date = January 1991 | pmid = 1824645 | doi = 10.1080/00325481.1991.11700800 }}</ref>
* [[dermatomyositis]]<ref>{{cite journal | vauthors = Sontheimer RD | title = The management of dermatomyositis: current treatment options | journal = Expert Opinion on Pharmacotherapy | volume = 5 | issue = 5 | pages = 1083–99 | date = May 2004 | pmid = 15155110 | doi = 10.1517/14656566.5.5.1083 | s2cid = 9829484 }}</ref>
* [[Bloom syndrome]]<ref>{{cite journal | vauthors = Aljarad S, Alhamid A, Rahmeh AR, Alibraheem A, Wafa A, Alachkar W, Aljarad Z, Aziz G | display-authors = 6 | title = Bloom syndrome with myelodysplastic syndrome that was converted into acute myeloid leukaemia, with new ophthalmologic manifestations: the first report from Syria | journal = Oxford Medical Case Reports | volume = 2018 | issue = 12 | pages = omy096 | date = December 2018 | pmid = 30410776 | pmc = 6217711 | doi = 10.1093/omcr/omy096 }}</ref>
* [[Rosacea]], a long-term skin condition characterized by a red rash, usually on the face.

Lupus causes up to 96% of all cases of malar rash.<ref name=":1" /> Where lupus is suspected, further [[medical test]]s and a detailed history and examination are necessary to [[differential diagnosis|differentiate]] it from other conditions.{{citation needed|date=August 2015}} These tests may include a test for the presence of [[anti-nuclear antibody]] in the blood as a [[screening (medicine)|screening]] test, which is not specific for lupus erythematosus.{{Citation needed|date=December 2020}}

== Epidemiology ==
A malar rash is present in approximately 46–65% of people with lupus,<ref name="Houman2004" /><ref name=":2" /> with an average of 57% of lupus patients having it across all populations.<ref name=":1" /> This percentage varies between different populations.<ref name="Houman2004">{{cite journal | vauthors = Houman MH, Smiti-Khanfir M, Ben Ghorbell I, Miled M | title = Systemic lupus erythematosus in Tunisia: demographic and clinical analysis of 100 patients | journal = Lupus | volume = 13 | issue = 3 | pages = 204–11 | year = 2004 | pmid = 15119551 | doi = 10.1191/0961203303lu530xx | s2cid = 30569636 }}</ref><ref name=":2">{{cite journal | vauthors = Vilá LM, Alarcón GS, McGwin G, Friedman AW, Baethge BA, Bastian HM, Fessler BJ, Reveille JD | display-authors = 6 | title = Early clinical manifestations, disease activity and damage of systemic lupus erythematosus among two distinct US Hispanic subpopulations | journal = Rheumatology | volume = 43 | issue = 3 | pages = 358–63 | date = March 2004 | pmid = 14623949 | doi = 10.1093/rheumatology/keh048 | doi-access = free }}</ref>

== History ==
A malar rash is often known more [[Colloquialism|colloquially]] as a butterfly rash due to its distinctive appearance.<ref name=":0" />

== See also ==

* [[Malar flush]]

== References ==
{{reflist}}

== External links ==
* {{cite web | title = Malar ("butterfly") rash, patient with SLE, gross | url = http://library.med.utah.edu/WebPath/IMMHTML/IMM009.html | work = The Internet Pathology Laboratory for Medical Education | publisher = The University of Utah Eccles Health Sciences Library }}
*{{MedlinePlusEncyclopedia|000435|Systemic lupus erythematosus}}

[[Category:Dermatologic terminology]]