Roseola

Template:Short description Template:Distinguish Template:Infobox medical condition (new) Roseola, also known as sixth disease, is an infectious disease caused by certain types of human herpes viruses.<ref name=CDC2017>Template:Cite journal</ref> Most infections occur before the age of three.<ref name=St2014>Template:Cite journal</ref> Symptoms vary from absent to the classic presentation of a fever of rapid onset followed by a rash.<ref name=St2014/><ref name=CDC2017/> The fever generally lasts for three to five days, while the rash is generally pink and lasts for less than three days.<ref name=St2014/> Complications may include febrile seizures, with serious complications being rare.<ref name=St2014/><ref name=CDC2017/>

It is caused by human herpesvirus 6 (HHV-6A, HHV-6B) or human herpesvirus 7 (HHV-7).<ref name=St2014/> Spread is usually through the saliva of those who are otherwise healthy.<ref name=St2014/><ref name=CDC2017/> However, it may also spread from the mother to the baby during pregnancy.<ref name=St2014/> Diagnosis is typically based on symptoms and does not need to be confirmed with blood tests (PCR or antigen).<ref name=St2014/> Low numbers of white blood cells may also be present.<ref name=St2014/>

Treatment includes sufficient fluids and medications to treat the fever.<ref name=St2014/> Nearly all people are infected at some point.<ref name=CDC2017/> Males and females are affected equally often.<ref name=St2014/> The disease may reactivate in those with a weakened immune system and may result in significant health problems.<ref name=CDC2017/>

The disease was first described in 1910 while the causal virus was isolated in 1988.<ref name="St2014" /> The name "sixth disease" comes from its place on the standard list of rash-causing childhood diseases, which also includes measles (first), scarlet fever (second), rubella (third), Dukes' disease (fourth, but is no longer widely accepted as distinct from scarlet fever), and erythema infectiosum (fifth).<ref>Template:Citation</ref>

Signs and symptoms

Fever

Symptoms begin with a three to six-day febrile illness.<ref name=":2" /><ref name=":3">Template:Cite book</ref> During this time, temperatures can peak above 40 °C and children can experience increased irritability with general malaise.<ref name=":3" /> Many children in the febrile phase feel well, engaged, and alert. For these patients, fever is usually diagnosed incidentally.<ref name=":3" />

The most common complication (10-15% of children between 6 and 18 months) and most common cause of hospitalization in children with primary infection of HHV-6B is febrile seizures which can precipitate status epilepticus due to the sudden rise in body temperature.<ref name=":4">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Rash

Once the febrile phase subsides, a rash develops. The rash sometimes presents one or two days after the fever resolves.<ref name=":3" /> The rash is classically described as an erythematous morbilliform exanthem<ref name=":2" /> and presents as a distribution of soft pink, discrete, and slightly raised lesions each with a 2-5mm diameter.<ref name=":2" /><ref name=":3" /><ref name=":4" /> It classically begins on the trunk (torso) and spreads outward to the neck, extremities, and face. This pattern is referred to as a centrifugal spread.<ref name=":2" /> Usually, peeling and itching are not characteristic of this rash.<ref name=":3" /> This phase can last anywhere from several hours to 2 days.<ref name=":2" /><ref name=":3" /><ref name=":4" /><ref>Roseola – Topic Overview Template:Webarchive, webmd.com</ref><ref name=":5" /><ref>Measles Rash Template:Webarchive, webmd.com</ref>

Other symptoms

A small percentage of children acquire HHV-6 with few signs or symptoms of the disease.<ref name=":5" /> Children with HHV-6 infection can also present with myringitis (inflammation of the tympanic membranes),<ref name=":2" /> upper respiratory symptoms,<ref name=":4" /><ref>Template:Cite journal</ref> diarrhea, and a bulging fontanelle.<ref name=":4" /> In addition, children can experience pharyngitis with lymphoid hyperplasia seen on the soft palate and swelling of the eyelids.<ref name=":3" /> These symptoms usually present during the febrile phase of roseola.<ref name=":4" /> Cervical and postoccipital lymphadenopathy can also be seen, but this generally presents 2–4 days after the onset of the febrile phase.<ref name=":4" /><ref>Template:Cite journal</ref>

In rare cases, HHV-6 can become active in an adult previously infected during childhood and can show signs of mononucleosis.<ref name="pmid10774474">Template:Cite journal</ref>

Cause

File:Hhv-6 (1).jpg

Electron micrograph of HHV-6

There are nine known human herpesviruses. Of these, roseola has been linked to two: human herpesvirus 6 (HHV-6) and human herpesvirus 7 (HHV-7), which are sometimes referred to collectively as Roseolovirus.<ref name=":4" /> These viruses are of the Herpesviridae family and the Betaherpesvirinae subfamily, under which Cytomegalovirus is also classified.<ref name=":4" /> HHV-6 has been further classified into HHV-6A and HHV-6B, two distinct viruses that share 88% of the same DNA makeup, with HHV-6B the most common cause of roseola.<ref name=":2">Template:Cite journal</ref><ref name=":0">Template:Cite journal</ref>

After infection, these viruses enter a latent phase. Roseola caused by HHV-7 has been linked to the ability of HHV-7 infection to reactivate latent HHV-6.<ref name=":4" />

Spread

After exposure to roseola, the causative virus becomes latent in its host but is still present in saliva, skin, and lungs.<ref name=":4" /> HHV-6 is thought to be transmitted from previously exposed or infected adults to young children by shedding the virus through saliva.<ref name=":5">Template:Cite book</ref> Even so, most cases of roseola are transmitted without known exposure.<ref name=":3" />

Diagnosis

The diagnosis of roseola is made clinically based on the presence of the two phases: fever and rash.<ref name=":3" /> Laboratory testing is seldom used as the results do not alter the management of the disease.<ref name=":4" /> An exception is in people who are immunocompromised in whom serologic tests with viral identification can be used to confirm the diagnosis.<ref name=":5" />

Roseola should be differentiated based on symptoms from other similar-appearing illnesses, such as rubella, measles, fifth disease, scarlet fever, and drug reactions.<ref name=":5" />

Prevention

Many viruses can cause roseola and are shed by carriers without symptoms. Because of this and the fact that most children with the disease are not seriously ill, there is no particular method of prevention.<ref name=":3" /> Proper hygienic measures, like regular handwashing, can be implemented as a routine prevention method. Those exposed or infected have been shown to shed the virus for the rest of their lives.<ref name=":6" /> No current guidelines exist regarding children staying home or away from child care when infected.<ref name=":6">Template:Cite journal</ref>

Treatment

Most cases of HHV-6 infection improve on their own.<ref>Template:Cite journal</ref> Because of this, supportive care is the mainstay treatment.

The febrile phase can be managed using acetaminophen to control fever and prevent spikes in temperature which can lead to febrile seizures.<ref name=":4" /><ref name=":5" /> In the case of febrile seizures, medical advice should be sought, and treatment aggressively pursued.<ref name=":3" /> Antiepileptic drugs are not recommended for patients who develop seizures from roseola.<ref name=":2" />

Once children have entered the rash phase, reassurance is important as this indicates the resolution of the infection.<ref name=":3" />

If encephalitis occurs in immunocompromised children, ganciclovir or foscarnet have inconsistently shown usefulness in treatment.<ref>Template:Cite journal</ref> Treatment of children who are immunocompromised centers around decreasing their levels of immunosuppression as much as possible.<ref name=":5" />

Prognosis

Children infected with roseola generally have a good prognosis. Most recover without intervention or long-term effects.<ref name=":2" /><ref name=":3" />

Epidemiology

Between the two human herpesvirus 6 types, HHV-6B has been detected much more frequently in hosts.<ref name=":0" /> HHV-6B has been shown to affect about 90% of children before the age of 3.<ref name=":1">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Out of these, 20% develop symptoms of roseola, also known as exanthem subitum.<ref name=":1" />

Roseola affects girls and boys equally worldwide year-round.<ref name=":3" /> Roseola typically affects children between six months and two years of age, with peak prevalence in children between 7 and 13 months old.<ref name=":3" /><ref name=":4" /> This correlates with the decrease in maternal antibodies, thus virus protection, that occurs at the age of 6 months.<ref name=":4" /> Out of all emergency department visits for children between ages 6 months and 12 months who have a fever, twenty percent of these are due to HHV-6.<ref name=":4" />

Many children exposed and infected can present without symptoms, which makes determining the incidence within the population difficult.<ref name=":3" />

History

John Zahorsky MD wrote extensively on this disease in the early 20th century, his first formal presentation was to the St Louis Pediatric Society in 1909 where he described 15 young children with the illness. In a JAMA article published on Oct 18, 1913, he noted that "the name 'Roseola infantilis' had an important place in the medical terminology of writers on skin diseases" but that descriptions of the disease by previous writers tended to confuse it with many other diseases that produce febrile rashes. In this JAMA article, Zahorsky reports on 29 more children with roseola and notes that the only condition that should seriously be considered in the differential diagnosis is German measles (rubella) but notes that the fever of rubella only lasts a few hours whereas the prodromal fever of roseola lasts three to five days and disappears with the formation of a morbilliform rash.<ref>John Zahorsky. Roseola Infantum. Journal of the American Medical Association. Oct 18, 1913 pages 1446-1450</ref>

Names

Country	Local name (language)	Translated name
Belgium	Driedagenkoorts (Dutch) Zesde ziekte (Dutch) Roséole (French)	"three-day fever" "sixth disease" -
China (PRC)	急疹 (Mandarin) jí zhěn (pinyin)	"fast rash"
Czech republic	Šestá nemoc (Czech)	"sixth disease"
Denmark	Tredagesfeber (Danish)	"three-day fever"
Estonia	Roseool, kolme päeva palavik	Roseola/three day fever
Finland	Vauvarokko (Finnish)	"baby measles"
France	Roséole	"Roseola"
Germany	Drei-Tage-Fieber (German)	"Three-day fever"
Greece	Αιφνίδιο εξάνθημα (Greek)	"sudden rash"
Hungary	Háromnapos láz (Hungarian) Hatodik betegség (Hungarian)	"three-day fever" "sixth disease"
Iceland	Mislingabróðir (Icelandic)	"measles' brother"
Israel	Adamdemet, אדמדמת, אביבית (Hebrew)	"rose/pink rash"
Italy	Sesta malattia (Italian)	"sixth disease"
Japan	突発性発疹 (Japanese) toppatsuseihosshin	"fast/sudden rash"
Korea (South)	돌발진 (Korean) Dolbaljin	"fast/sudden rash"
Malaysia	Campak halus (Malay)	"small/tiny measles"
Netherlands	Zesde ziekte (Dutch)	"sixth disease"
Norway	Fjerde barnesykdom (Norwegian)<ref>Nylander, Gro (2009) "Lille venn, hva nå?"</ref>	"fourth disease"
Philippines	Tigdas Hangin (Tagalog)	"wind measles"
Poland	Gorączka trzydniowa (Polish)	"Three-day fever"
Romanian	Roseola eruptia subita	Roseola
Russia	Розеола (Russian) шестая болезнь (Russian)	Roseola "sixth disease"
Singapore	Jiǎ má 假麻 (Chinese)	"false measles"
Slovakia	Šiesta (detská) choroba (Slovak)	"sixth disease"
Slovenia	Šesta bolezen (Slovenian)	"sixth disease"
South Africa	Roseola (English)	"Roseola"
Sweden	Tredagarsfeber Sjätte sjukan (Swedish)	"three-day fever" Sixth disease
Taiwan	Méiguī zhěn 玫瑰疹 (Chinese)	"rose rash"
Turkey	Altıncı hastalık (Turkish)	"sixth disease"
Vietnam	Sốt phát ban (Vietnamese)	"baby rash"

Research

HHV-6 has been tentatively linked with neurodegenerative diseases.<ref>Template:Cite journal</ref>

See also

• Fifth disease

External links

• Template:DermNet