Roseola infantum (Human herpesvirus 6) is a childhood infection. Symptoms are high fever followed by rash. Fever lasts 3-4 days. Maculopapular rash follows defervescence of fever. Rash begins on neck & trunk, spreads to extremities, and lasts for a few hours to 2 days.
CASES/YEAR
960,000 (US); 19,200,000 (Global)
OTHER NAMES
Exanthem subitum; Sixth disease; Human herpesvirus 6; HHV-6 infection; HHV-7 infection;
INCUBATION
10 days (range of 5-15 days); [CCDM]
INITIAL SYMPTOMS
High fever followed by rash; Fever lasts 3-4 days; Maculopapular rash follows defervescence of fever; Rash begins on neck & trunk, spreads to extremities, and lasts for a few hours to 2 days; [PPID, p. 1892]
COMMENTS
FINDINGS:
An illness of children, usually under the age of two, roseola begins with several days of high fever. A maculopapular rash on the trunk appears when the fever lyses, or shortly thereafter. Transmission is thought to occur through saliva. [CCDM, p. 205] The papular rash appears on the trunk, sparing the face. It lasts a few hours or as long as two days. The CBC may show mild leukocytosis followed by mild leukopenia. [ID, p. 1222] Febrile convulsions occur in 10% of cases. Cervical lymphadenopathy may be present. [5MCC-2020] A febrile illness without rash is also reported. Lymphadenopathy is common but appears later. Conjunctivitis may be present. [Cohen, p. 79]
COMPLICATIONS:
Complications include febrile convulsions and, rarely, meningoencephalitis and hepatitis. [CCDM, p. 205] Other clinical syndromes (in addition to roseola, infantile fever, and mononucleosis) are encephalitis, hepatitis, and infections in immunocompromised hosts. HHV-6 can cause encephalitis/cranial neuropathy in healthy children. [PPID, p. 1892-3] Recent studies using molecular techniques (PCR) have implicated HHV-6 in 18% of 87 patients with viral myocarditis. [Cohen, p. 447]
DIAGNOSTIC
PCR; Paired sera; IgM appears 1 week after onset and disappears by 3-4 weeks; [CCDM] Usually a clinical diagnosis; Paired sera; [PPID]
SIGNS & SYMPTOMS
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>fever
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E rhinitis
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G diarrhea
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G nausea, vomiting
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H leukocytosis
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H leukopenia
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H lymphadenopathy
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H splenomegaly
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H thrombocytopenia
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N seizure
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R cough
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S papules or plaques
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S rash (exanthem)
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*encephalitis
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*hepatitis
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*meningitis
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*myocarditis
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*pneumonitis
ENTRY
Inhalation, Skin or Mucous Membranes (Includes Conjunctiva)
TREATMENT
Ganciclovir or foscarnet have been used in immunocompromised patients, but no controlled studies have demonstrated effectiveness; [PPID, 1895]
REFERENCES FOR CASES/YEAR
1. (US) The disease peaks at age of 9-21 months; 80% are seropositive by age 24 months; Most children have fever, fussiness, and diarrhea; A minority develop roseola; 4 million born/year in US; Guesstimate: in two years 80% of 8 million have been infected = 6.4 million; Assume that only 30% develop roseola, then 30% X 6.4 million = 1.9 million for 2 years and 960,000 for 1 year;
2. (Global) Estimate global cases as 20 X US cases;