# Roseola
**Roseola** (also called roseola infantum, exanthem subitum, sixth disease, or three-day fever) is a common viral illness of infants and young children, marked by three to four days of high fever followed by the sudden appearance of a rose-pink rash as the fever falls. [Human herpesvirus 6](https://www.edgepedia.org/human-herpesvirus-6), chiefly the HHV-6B variant, is the major cause, with human herpesvirus 7 accounting for a smaller share of cases[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf). The illness is generally benign and self-limited, and most children recover within a week of the onset of fever[2](https://www.mayoclinic.org/diseases-conditions/roseola/diagnosis-treatment/drc-20377289).
| Key fact | Detail |
|---|---|
| Cause | Human herpesvirus 6, mainly HHV-6B; HHV-7 is a less frequent cause, and enterovirus or parvovirus rarely[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf) |
| Typical course | High fever of 39 to 40.5 °C lasting 3 to 4 days, then a discrete rose-pink macular or maculopapular rash of 2 to 3 mm appearing at defervescence[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf) |
| Age peak | Most frequent between 7 and 13 months of age; rare after 4 years[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf) |
| Burden | Accounts for 10 to 45% of febrile illnesses in infants in the United States and about 12% of emergency department visits for febrile infants[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf) |
| Common complication | Febrile seizures in 10 to 15% of affected children during the febrile period[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf) |
| Treatment | No specific treatment; acetaminophen or ibuprofen for fever, rest, and fluids; aspirin is avoided in children because of its link to Reye's syndrome[2](https://www.mayoclinic.org/diseases-conditions/roseola/diagnosis-treatment/drc-20377289) |
| Contagion | Spread through saliva and respiratory droplets; a child is considered no longer contagious after the fever has been gone for 24 hours[3](https://www.mayoclinic.org/diseases-conditions/roseola/symptoms-causes/syc-20377283) |
## Clinical course
The illness begins with an abrupt onset of high fever, characteristically between 39 and 40.5 °C, which may be intermittent or constant and lasts 3 to 4 days[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf). During the febrile period most children otherwise look well and remain happy, active, alert, and playful, although some become restless or irritable when the fever is high[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf). The incubation period for HHV-6 is 9 to 10 days[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf).
**The rash.** With sudden resolution of the fever, the typical exanthem appears, which is the origin of the name exanthem subitum, Latin for "sudden rash"[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf). The eruption consists of discrete, rose-pink, circular or elliptical macules or maculopapules measuring 2 to 3 mm in diameter. It begins on the trunk and spreads to the neck, face, and extremities, typically blanches under pressure, and subsides in 2 to 4 days without sequelae. Desquamation and itching are characteristically absent[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf). On darker skin tones the rash may be harder to see and appear as a faint red or purple color[4](https://www.healthychildren.org/English/health-issues/conditions/skin/Pages/Roseola-Infantum.aspx).
Other findings can include suboccipital, postauricular, and cervical lymphadenopathy, palpebral and periorbital edema (Berliner sign), erythematous maculopapular spots on the soft palate and uvula (Nagayama's spots), and a bulging fontanelle in the absence of meningitis or encephalitis[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf).
## Cause
Roseola infantum is most frequently caused by human herpesvirus 6 (HHV-6), less frequently by HHV-7, and rarely by enterovirus and parvovirus[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf). HHV-6 was discovered in 1986 by Dharam Ablashi, Robert Gallo, and Zaki Salahuddin at the US National Cancer Institute and was originally called human B-lymphotropic virus (HBLV); it was first isolated from AIDS patients with cancer and lymphoproliferative disorders[5](https://hhv-6foundation.org/what-is-hhv-6/history-of-hhv-6). In 1988, Koichi Yamanishi and coworkers showed that HHV-6 was the cause of exanthem subitum, isolating the virus from peripheral-blood mononuclear cells of affected infants and demonstrating seroconversion[6](https://www.nejm.org/doi/full/10.1056/NEJM199307153290311).
HHV-6 has two variants, HHV-6A and HHV-6B, which share more than 90% genome sequence homology and were proposed in 2011 to be recognized as distinct viral species[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf) • [5](https://hhv-6foundation.org/what-is-hhv-6/history-of-hhv-6). HHV-6B is the major cause of roseola infantum and accounts for more than 95% of primary HHV-6 infections in children in the United States and the United Kingdom, while HHV-6A is more common in African children and is an uncommon cause of the disease[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf). Both viruses are trophic for CD4+ T lymphocytes and establish lifelong latency after primary infection, which may reactivate[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf).
Transmission most likely results from asymptomatic shedding of the virus in the saliva and respiratory droplets of caregivers, siblings, or other close contacts, especially during the convalescent phase; the main route is inoculation of the oropharynx with replication in the salivary glands[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf). Roseola rarely causes communitywide outbreaks, and its peak incidence is in spring and autumn[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf) • [3](https://www.mayoclinic.org/diseases-conditions/roseola/symptoms-causes/syc-20377283).
## Diagnosis
The diagnosis is mainly clinical, based on the characteristic pattern of high fever for 3 to 4 days followed by the sudden appearance of a morbilliform (measles-like rash; roseola's rash pattern aids diagnosis) rash at defervescence[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf). Laboratory investigations are usually unnecessary given the benign and self-limited nature of the illness, although serologic tests, virus culture, and PCR assays are available[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf).
**Distinguishing features.** Roseola can be confused with measles, rubella, scarlet fever, erythema infectiosum, hand, foot, and mouth disease, infectious mononucleosis, [Kawasaki disease](https://www.edgepedia.org/kawasaki-disease), and drug allergy[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf). Two features help separate it: children with roseola have a significantly higher mean temperature than those with other febrile exanthems, with the great majority above 39 °C, and the rash appears only as the fever falls, whereas a measles rash begins on the head while a roseola rash often starts on the chest or back[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf) • [2](https://www.mayoclinic.org/diseases-conditions/roseola/diagnosis-treatment/drc-20377289). Because children with roseola may have inflamed tympanic membranes and sterile pyuria, they are sometimes misdiagnosed with acute otitis media or a urinary tract infection and treated unnecessarily[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf).
## Treatment and self-care
There is no specific treatment for roseola; like most viruses, it needs to run its course, and most children recover within a week of the onset of fever[2](https://www.mayoclinic.org/diseases-conditions/roseola/diagnosis-treatment/drc-20377289). With a health care provider's advice, nonprescription fever and pain medications made for infants or children, such as acetaminophen or ibuprofen, may be used[2](https://www.mayoclinic.org/diseases-conditions/roseola/diagnosis-treatment/drc-20377289). Home care includes rest, lightweight clothing, and plenty of clear fluids to prevent dehydration[2](https://www.mayoclinic.org/diseases-conditions/roseola/diagnosis-treatment/drc-20377289).
Aspirin requires caution in children and teenagers: children and teenagers recovering from chickenpox or flu-like symptoms should never take aspirin, because aspirin has been linked to Reye's syndrome, a rare but potentially life-threatening condition[2](https://www.mayoclinic.org/diseases-conditions/roseola/diagnosis-treatment/drc-20377289). The rash itself is harmless, needs no creams or ointments, and clears in a few days[2](https://www.mayoclinic.org/diseases-conditions/roseola/diagnosis-treatment/drc-20377289). For people with weakened immune systems, some health care providers may prescribe the antiviral drug ganciclovir[2](https://www.mayoclinic.org/diseases-conditions/roseola/diagnosis-treatment/drc-20377289). There is no vaccine to prevent roseola[3](https://www.mayoclinic.org/diseases-conditions/roseola/symptoms-causes/syc-20377283).
## Complications
Febrile seizures, brought on by the sudden high fever, are the characteristic complication, occurring in 10 to 15% of children with roseola infantum during the febrile period, especially on the first day of fever[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf). Although frightening, febrile seizures in otherwise healthy children tend to be short-lived and are rarely harmful[3](https://www.mayoclinic.org/diseases-conditions/roseola/symptoms-causes/syc-20377283). A review of the literature covering 1994 through 2004 showed that seizures complicated primary HHV-6 infection in 17% of children who presented for medical care[7](https://pmc.ncbi.nlm.nih.gov/articles/PMC4267952/).
Serious complications are rare and occur more often in immunocompromised individuals, in whom roseola can be more severe or lead to pneumonia or encephalitis[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf) • [3](https://www.mayoclinic.org/diseases-conditions/roseola/symptoms-causes/syc-20377283). Rare reported complications include thrombocytopenia, mononucleosis, pneumonia, myocarditis, hepatitis, and Guillain-Barré syndrome[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf).
## Epidemiology and history
Roseola infantum occurs worldwide with no racial or geographical predilection, and the sex ratio is approximately equal[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf). Presumably maternally acquired antibodies protect most infants during the first few months of life. By 12 and 18 months of age, approximately 65% and 95% of children, respectively, have been infected, almost all children have acquired the infection by 2 years of age, and the disease is rare after 4 years[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf). Serologic studies similarly indicate that HHV-6 infects most children by the age of three years[8](https://www.nejm.org/doi/full/10.1056/NEJM199205283262201).
The condition was first described in the medical literature as a unique clinical entity by Robert Willan in 1809, and the term "roseola infantum" was coined by John Zahorsky in 1910[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf). It was the sixth common childhood exanthem to be named, after measles, scarlet fever, rubella, Filatov-Dukes disease, and erythema infectiosum, which is the source of the name "sixth disease"[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf). The etiologic agent was not identified until 1988, more than seven decades after Zahorsky's publication[1](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf).
## References
1. [Leung AKC, Lam JM, Barankin B, Leong KF, Hon KL (2024). Roseola Infantum: An Updated Review. Current Pediatric Reviews.](https://cumming.ucalgary.ca/sites/default/files/teams/82/communications/Roseola%20infantum%20%5BCPR%5D.pdf)
2. [Roseola: Diagnosis and treatment, Mayo Clinic](https://www.mayoclinic.org/diseases-conditions/roseola/diagnosis-treatment/drc-20377289)
3. [Roseola: Symptoms and causes, Mayo Clinic](https://www.mayoclinic.org/diseases-conditions/roseola/symptoms-causes/syc-20377283)
4. [Roseola in Babies and Toddlers, HealthyChildren.org (American Academy of Pediatrics)](https://www.healthychildren.org/English/health-issues/conditions/skin/Pages/Roseola-Infantum.aspx)
5. [History of HHV-6, HHV-6 Foundation](https://hhv-6foundation.org/what-is-hhv-6/history-of-hhv-6)
6. [Agut H (1993). Puzzles Concerning the Pathogenicity of Human Herpesvirus 6. New England Journal of Medicine 329:203-204.](https://www.nejm.org/doi/full/10.1056/NEJM199307153290311)
7. [Clinical Impact of Primary Infection with Roseoloviruses, PMC](https://pmc.ncbi.nlm.nih.gov/articles/PMC4267952/)
8. [Primary Human Herpesvirus 6 Infection in Young Children. New England Journal of Medicine 1992;326:1445-50.](https://www.nejm.org/doi/full/10.1056/NEJM199205283262201)
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*Topic: Encyclopedia › Life and health › Microorganisms and fungi › Viruses and acellular agents › Viruses of animals and humans › Herpes-, polyoma-, and papillomaviruses (DNA viruses) › Betaherpesviruses*
*Initially written Sep 17, 2026 · Reviewed: Oct 21, 2026 · Edited: Oct 15, 2026; Oct 21, 2026 · Last review: Oct 21, 2026*
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License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license