Editing Dengue fever (section)

== Signs and symptoms ==

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 | caption2          = Clinical course of dengue fever
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Typically, people infected with dengue virus are [[asymptomatic]] or have only mild symptoms such as an uncomplicated fever (80%).<ref name=White10>{{cite journal | vauthors = Whitehorn J, Farrar J | title = Dengue | journal = British Medical Bulletin | volume = 95 | pages = 161–173 | year = 2010 | pmid = 20616106 | doi = 10.1093/bmb/ldq019 | s2cid = 215154729 | doi-access = free }}</ref><ref name=Euro10>{{cite journal | vauthors = Reiter P | title = Yellow fever and dengue: a threat to Europe? | journal = Euro Surveillance | volume = 15 | issue = 10 | pages = 19509 | date = March 2010 | pmid = 20403310 | doi = 10.2807/ese.15.10.19509-en | url = http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19509 | url-status = live | doi-access = free | archive-url = https://web.archive.org/web/20110707070425/http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19509 | archive-date = 7 July 2011 }}</ref> Others have more severe illness (5%), and in a small proportion it is life-threatening.<ref name=White10/><ref name=Euro10/> The [[incubation period]] (time between exposure and onset of symptoms) ranges from 3 to 14 days, but most often it is 4 to 7 days.<ref name=Gubler2010>{{cite book| vauthors = Gubler DJ | veditors = Mahy BW, Van Regenmortel MH |title=Desk Encyclopedia of Human and Medical Virology|chapter=Dengue viruses|publisher=Academic Press|location=Boston|year=2010|isbn=978-0-12-375147-8|chapter-url=https://books.google.com/books?id=nsh48WKIbhQC&pg=PA372|pages=372–82|url-status=live|archive-url=https://web.archive.org/web/20160609195355/https://books.google.com/books?id=nsh48WKIbhQC&pg=PA372|archive-date=9 June 2016}}</ref>

The characteristic symptoms of mild dengue are sudden-onset fever, headache (typically located behind the eyes), muscle and joint pains, nausea, vomiting, swollen glands and a rash.<ref name="WHO2023" /><ref name="www.unicef.org-2024" /> If this progresses to severe dengue the symptoms are  severe abdominal pain, persistent vomiting, rapid breathing, bleeding gums or nose, fatigue, restlessness, blood in vomit or stool, extreme thirst, pale and cold skin, and feelings of weakness.<ref name="WHO2023" />

=== Clinical course ===
The course of infection is divided into three phases: febrile, critical, and recovery.<ref name="NEJM2012">{{cite journal | vauthors = Simmons CP, Farrar JJ, Nguyen V, Wills B | title = Dengue | journal = The New England Journal of Medicine | volume = 366 | issue = 15 | pages = 1423–1432 | date = April 2012 | pmid = 22494122 | doi = 10.1056/NEJMra1110265 | url = http://minerva-access.unimelb.edu.au/bitstream/11343/191104/1/Current%20Concepts%20-%20Dengue.pdf | access-date = 24 September 2019 | url-status = live | hdl-access = free | archive-date = 28 August 2021 | archive-url = https://web.archive.org/web/20210828054832/http://minerva-access.unimelb.edu.au/bitstream/handle/11343/191104/Current | hdl = 11343/191104 }}</ref>

The febrile phase involves [[high fever]] (40&nbsp;°C/104&nbsp;°F), and is associated with generalized pain and a headache; this usually lasts two to seven days.<ref name="WHO2023" /><ref name="Chen">{{cite journal | vauthors = Chen LH, Wilson ME | title = Dengue and chikungunya infections in travelers | journal = Current Opinion in Infectious Diseases | volume = 23 | issue = 5 | pages = 438–444 | date = October 2010 | pmid = 20581669 | doi = 10.1097/QCO.0b013e32833c1d16 | s2cid = 2452280 }}</ref> There may also be nausea, vomiting, a rash, and pains in the muscle and joints.<ref name="WHO2023" />

Most people recover within a week or so. In about 5% of cases, symptoms worsen and can become life-threatening. This is called '''severe dengue''' (formerly called ''dengue hemorrhagic fever'' or ''dengue shock syndrome'').<ref name=NEJM2012/><ref name="Peads10">{{cite journal | vauthors = Ranjit S, Kissoon N | title = Dengue hemorrhagic fever and shock syndromes | journal = Pediatric Critical Care Medicine | volume = 12 | issue = 1 | pages = 90–100 | date = January 2011 | pmid = 20639791 | doi = 10.1097/PCC.0b013e3181e911a7 | s2cid = 10135251 }}</ref> Severe dengue can lead to shock, internal bleeding, organ failure and even death.<ref name="Mayo-Clinic-Symptoms-2024">{{Cite web |title=Dengue fever - Symptoms and causes |url=https://www.mayoclinic.org/diseases-conditions/dengue-fever/symptoms-causes/syc-20353078 |access-date=2024-02-25 |website=Mayo Clinic |language=en |archive-date=26 February 2024 |archive-url=https://web.archive.org/web/20240226011216/https://www.mayoclinic.org/diseases-conditions/dengue-fever/symptoms-causes/syc-20353078 |url-status=live }}</ref> Warning signs include severe stomach pain, vomiting, difficulty breathing, and blood in the nose, gums, vomit or stools.<ref name="Mayo-Clinic-Symptoms-2024" />

During this period, there is leakage of plasma from the blood vessels, together with a reduction in [[platelet]]s.<ref name="Mayo-Clinic-Symptoms-2024" /> This may result in fluid accumulation in the [[thoracic cavity|chest]] and [[abdominal cavity]] as well as [[hypovolemia|depletion of fluid from the circulation]] and [[hypoperfusion|decreased blood supply to vital organs]].<ref name="Peads10" />

The recovery phase usually lasts two to three days.<ref name="Peads10" /> The improvement is often striking, and can be accompanied with severe [[itch]]ing and a [[Bradycardia|slow heart rate]].<ref name="Peads10" />

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| image1            = Early Dengue Fever Rash 2014.jpg
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| caption1          = The rash of dengue fever in the acute stage of the infection [[Blanch (medical)|blanches]] when pressed.
| image2            = Dengue recovery rash (White islands in red sea).jpg
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| caption2          = The rash that commonly forms during the recovery from dengue fever with its classic islands of white in a sea of red
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==== Complications and sequelae ====
[[Sequela|Complications]] following severe dengue include fatigue, somnolence, headache, concentration impairment and memory impairment.<ref name="NEJM2012" /><ref>{{cite journal | vauthors = Kalimuddin S, Teh YE, Wee LE, Paintal S, Sasisekharan R, Low JG, Sheth SK, Ooi EE | title = Chronic sequelae complicate convalescence from both dengue and acute viral respiratory illness | journal = PLOS Neglected Tropical Diseases | volume = 16 | issue = 8 | pages = e0010724 | date = August 2022 | pmid = 35981059 | pmc = 9426910 | doi = 10.1371/journal.pntd.0010724 | doi-access = free }}</ref> A pregnant woman who develops dengue is at higher risk of [[miscarriage]], [[low birth weight]], and [[Preterm birth|premature birth]].<ref>{{cite journal | vauthors = Paixão ES, Teixeira MG, Costa MD, Rodrigues LC | title = Dengue during pregnancy and adverse fetal outcomes: a systematic review and meta-analysis | journal = The Lancet. Infectious Diseases | volume = 16 | issue = 7 | pages = 857–865 | date = July 2016 | pmid = 26949028 | doi = 10.1016/S1473-3099(16)00088-8 | url = https://researchonline.lshtm.ac.uk/2537331/1/Systematic%20Literature%20Review%2020.11.docx | access-date = 5 December 2019 | url-status = live | archive-url = https://web.archive.org/web/20210828054827/https://researchonline.lshtm.ac.uk/id/eprint/2537331/1/Systematic | archive-date = 28 August 2021 }}</ref>

Children and older individuals are at a risk of developing complications from dengue fever compared to other age groups; young children typically suffer from more intense symptoms. Concurrent infections with [[tropical disease]]s<ref>{{cite journal | vauthors = Rothman AL | title = Immunity to dengue virus: a tale of original antigenic sin and tropical cytokine storms | journal = Nature Reviews. Immunology | volume = 11 | issue = 8 | pages = 532–543 | date = July 2011 | pmid = 21760609 | doi = 10.1038/nri3014 }}</ref> like the [[Zika virus]] can worsen symptoms and make recovery more challenging.<ref>Zanluca, C., & Duarte dos Santos, C. N. (2016). ''Zika virus – an overview. Microbes and Infection'', 18(5), 295-301. ''Retrieved 27 September 2024''</ref>