II. Causes
- Human Herpes Virus (Herpesviridae)
-
Human Herpes Virus (HHV) Type 6 (most common)
- HH6 and HH7 also suspected primary causes of Pityriasis Rosea
- Other viruses may, less commonly, cause a similar presentation
- HHV 7
- Enterovirus
- Coxsackievirus
- Adenovirus
- Parainfluenza VIrus
III. Epidemiology
- Peak ages: 6-18 months
- Peak seasonal distribution in late summer and early fall
- Transmission is typically from asymptomatic shedding from older siblings and adults
- Very common
- Prevalence of Antibody to HHV-6 approaches 100% by 3 years of age
IV. Signs
- Days 1-2
- Anorexia
- Vomiting
- Diarrhea (variable)
- Mild cough or Rhinorrhea (variable)
- Occipital Lymphadenopathy
- Days 2-3
- High Fever starts (103 to 106 F)
- Occurs at onset without accompanying localizing signs
- Fever Without Focus
- Often a diagnostic dilemma until the rash appears
- Child appears well without focal findings
- Mild cough or Rhinorrhea may be present
- Mild Diarrhea may be present
- High Fever starts (103 to 106 F)
- Day 4
- Rash onset as fever abates
- Fine, 2-5 mm, erythematous or pink Macules and Papules (maculopapular rash)
- Pink, blanchable, almond shaped Macules
- Most common centrally on the trunk and neck (may spread peripherally/centrifugally to extremities)
- Macules become confluent with one another and then fade within hours to 2 days (up to 4 days)
- Other associated findings
- Viral Sialoadenitis (especially Parotid Gland)
- Oral Lesions (in up to two thirds of patients)
- Erythematous Papules on the Soft Palate and uvula
- Rash onset as fever abates
V. Differential Diagnosis
VI. Complications
-
Febrile Seizures (common cause)
- Occurs in 10-15% of Roseola cases
VIII. References
- Latessa (2012) AAFP Board Review Express, San Jose
- Allmon (2015) Am Fam Physician 92(3): 211-6 [PubMed]
- Longfellow (2023) Am Fam Physician 107(6): 649-50 [PubMed]
- Wilson (2026) Am Fam Physician 114(4): 345-57 [PubMed]