History and exam

Key diagnostic factors

common

age under 2 years

Human herpesvirus (HHV)-6 is found worldwide and 90% of children are seropositive by the age of 24 months.[1]

Primary infection by HHV-7 occurs in approximately 50% of children by the age of 2 years.[10]

immunosuppression

Reactivation of the HHV-6 latent virus is most commonly seen in patients who are immunosuppressed or in the weeks to months following bone marrow or organ transplantation.[12]

high fever

A sudden onset of high fever >39.5°C (103.0°F).[3]

Typically peaks in early evening and persists for 3 to 7 days.

exanthem

The typical exanthem presents with the resolution of fever and consists of 3- to 5-mm pink-red macules and papules on the trunk, neck, and proximal extremities, and occasionally on the face.

Other diagnostic factors

common

diarrhoea

Seen in up to 65% of children.[12] 

abdominal pain

Abdominal pain is common.[15]

Nagayama's spots

An enanthem composed of red papules on the soft palate and uvula has been described.

Junctional uvulo-palatoglossal ulcers have also been described.

tympanic membrane inflammation

Historically noted in the large majority of children with roseola.

upper respiratory symptoms

Mild cough and rhinorrhoea.

uncommon

seizures

Up to 15% of children will present with a seizure episode, and primary HHV-6 infection has been associated with approximately one third of first-time childhood febrile seizures.[12][17]

Other focal neurological signs including encephalopathy and altered level of consciousness have been reported.

peri-orbital oedema

Most common during the febrile phase.

bulging anterior fontanelle

Present in up to 25% of infants (in whom the skull hasn't already fused).[14]

cervical, occipital, or post-auricular lymphadenopathy

Cervical, occipital, and post-auricular lymphadenopathy has been described.

Risk factors

strong

age under 2 years

Human herpesvirus (HHV)-6 is found worldwide and 90% of children are seropositive by the age of 24 months.[1]

Primary infection by HHV-7 occurs in approximately 50% of children by the age of 2 years.[10]

immunosuppression

Reactivation of the HHV-6 latent virus is commonly seen in patients who are immunosuppressed or in the weeks to months following bone marrow or organ transplantation.[11][12]

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