HHV Type 6

Snapshot

A 6-month old boy born at full term to a 26-year-old mother is brought to the emergency room for high fevers and seizure lasting less than 1 minute. The mother reports that he has been healthy without any medical problems and has met all 6-month milestones. Two days ago, he began having high fevers and some irritability, and today, he had a seizure. He was admitted for infectious workup. The next day, his fever resolved and he developed a morbilliform blanching rash on his trunk.

Introduction

Classification
- human herpesvirus-6 (HHV-6)
  - an enveloped, linear, double-stranded DNA virus
  - transmission via respiratory secretions
  - causes roseola infantum (exanthem subitum)
Epidemiology
- demographics
  - infants > children > adults
- location
  - skin
- risk factors
  - immunosuppression
  - transplant recipients
Pathogenesis
- the virus replicates in salivary glands
- the virus is latent in lymphocytes and monocytes
- may contribute to tumor progression in Kaposi sarcoma and lymphoma
Associated conditions
- may be associated with human herpesvirus-7
Prevention
- no vaccines are available
Prognosis
- does not commonly recur
disease is self-limited

Presentation

Symptoms
- high fever for 3 days
- may have febrile seizures
- no upper respiratory symptoms
Physical exam
- light pink morbilliform rash that develops after the fever resolves
  - blanching
  - discrete and irregular macules and papules
  - lasts 2 days
- Nagayama spots
erythematous papules on the mucosa of soft palate and uvula

Studies

Differential

Measles
- distinguishing factor
  - cough, conjunctivitis, coryza, Koplik spots, and confluent rash excluding palms and soles
Rubella
- distinguishing factor
post-auricular lymphadenopathy with non-confluent rash that desquamates

Treatment

Complications