Paeds · infectious-diseases
Common viral exanthems, including roseola and erythema infectiosum
Also known as Roseola infantum · Exanthem subitum · Sixth disease · Human herpesvirus 6 infection · Erythema infectiosum · Fifth disease · Slapped cheek disease · Parvovirus B19 infection
Fellowship topic on the common benign viral exanthems of childhood, with roseola infantum (human herpesvirus 6 and 7) and erythema infectiosum (parvovirus B19) as the flagship entities. Covers the fever-versus-rash timing that anchors the diagnosis, the host-dependent parvovirus B19 disease spectrum (transient aplastic crisis in haemolytic anaemia, fetal hydrops in pregnancy, pure red cell aplasia in immunodeficiency), the rash differential that separates a self-limiting exanthem from meningococcal disease, Kawasaki disease and staphylococcal scalded skin, the selective use of serology and PCR, supportive management of the well child, urgent pathways for the high-risk contact, and the public-health layer of exclusion and counselling.
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Target exams
Red flags
- A non-blanching purpuric or petechial rash in a febrile child — meningococcal disease until proven otherwise, regardless of a viral exanthem going around the school
- Fever for five or more days with conjunctivitis, red cracked lips, strawberry tongue or extremity change — Kawasaki disease; do not attribute to a benign viral exanthem
- A non-immune pregnant contact of a child with parvovirus B19 — risk of fetal hydrops and intrauterine death; needs urgent serology and fetal-medicine referral
- A child with sickle cell or other chronic haemolytic anaemia and parvovirus B19 — transient aplastic crisis with a precipitous, life-threatening haemoglobin fall
- An immunocompromised child with persistent parvovirus B19 anaemia — pure red cell aplasia that will not resolve without intravenous immunoglobulin and reduction of immunosuppression
- A toxic, drowsy or rapidly deteriorating child, or one with meningism — investigate for sepsis and meningitis before accepting a benign viral diagnosis
Life stages
Care settings
Clinical exam formats
Board mappings
- General Paediatrics and Infectious Diseases: common viral exanthems — roseola and erythema infectiosum — clinical recognition, complications and host-dependent risk
- Neurodevelopmental and behavioural paediatrics: febrile seizures including HHV-6-related seizures
- Renewed curriculum — Infectious diseases: parvovirus B19 and human herpesvirus 6 recognition, host-dependent complications and the rash differential
- Community and population child health: school exclusion, pregnancy contact tracing and the public-health response to parvovirus outbreaks
- General Paediatrics: the febrile infant with rash — distinguishing benign viral exanthem from sepsis, Kawasaki disease and meningococcal disease
- Public health: exclusion guidance and counselling of pregnant contacts in parvovirus B19
- Long Case / Structured discussion: the non-immune pregnant woman exposed to fifth disease, or the child with sickle cell disease and aplastic crisis — host-dependent parvovirus B19 disease
- Communication station: explaining a benign viral exanthem and reassuring a family while protecting the high-risk contact
- Level 2 / 3 — Infection: common viral exanthems of childhood; clinical features, complications and when to investigate
- Public health: exclusion guidance and the pregnant-contact pathway for parvovirus B19
- Foundation of Practice (FOP): roseola and erythema infectiosum clinical features, and the acute febrile-rash differential
- Applied Knowledge in Practice (AKP): host-dependent parvovirus B19 disease — pregnancy, haemolytic anaemia and immunodeficiency
- History-taking and management: the febrile infant with a rash, or the pregnant woman with a parvovirus contact
- Communication: explaining a benign viral exanthem and the pregnancy-contact pathway to a family
- General Pediatrics Content Outline — common viral exanthems: roseola and fifth disease; diagnosis, complications and host-dependent risk
- Infectious Diseases: parvovirus B19 serology and PCR, transient aplastic crisis and congenital infection
- Rheumatology / Haematology: parvovirus arthropathy and transient red-cell aplasia
- Patient Care: recognition of benign viral exanthems and identification of the high-risk host requiring escalation
- Systems-Based Practice and Population Health: exclusion guidance, pregnancy-contact tracing and counselling
- Medical Knowledge: HHV-6 and parvovirus B19 pathophysiology and the host-dependent disease spectrum
- Medical Expert: roseola and erythema infectiosum diagnosis, complications and the rash differential
- Health Advocate and Collaborator: pregnancy-contact pathway, haemoglobinopathy awareness and public-health coordination
- Communicator: explaining a benign exanthem and protecting the high-risk contact
The two flagship exanthems at a glance
Roseola (sixth disease)
Erythema infectiosum (fifth disease)
Examiners love the historical numbering because it groups the febrile-rash illnesses the bedside brain has to separate. Measles is first, scarlet fever second, rubella third, the fourth is disputed, fifth disease is parvovirus B19, and roseola is sixth. The numbering is a memory scaffold that still anchors the differential today — when you see a febrile child with a rash, your mind runs down this list and asks which one it is, and which dangerous mimic it is not. The point is the reasoning it triggers, not reciting the list. [2] [5]
Overview & Definition
Picture an eighteen-month-old brought to the emergency department after three days of fever that has hovered around 39.5 °C. The parents are frightened by the height of the temperature, yet the child is reaching for toys and smiling between spikes, the observations are normal for age, and there is no focus on examination. You send them home with safety-net advice. That evening the fever breaks, and the next morning the mother phones in a panic: the child is covered in a rash. That sequence — high fever in a well child, then a rash appearing as the fever resolves — is roseola, and recognising it spares the child and family an avalanche of unnecessary tests and antibiotics. [6] [7]
Now picture a different child, a six-year-old sent home from school because of "slapped cheeks". She is afebrile and playing, her cheeks are an angry red that fades at the nose and mouth, and over the next two days a faint lacelike rash appears on her arms and the backs of her thighs. Her mother, twenty weeks pregnant, asks if it is dangerous. That is erythema infectiosum, and the question that matters is not about the child — she will be fine — but about her pregnant mother, because parvovirus B19 can cross the placenta and stop the fetal bone marrow making red cells. [1] [3]
A viral exanthem is a rash produced by a systemic viral infection, either by the virus damaging skin cells directly or, more often, by the immune response to the virus. The common viral exanthems of childhood are mostly benign, self-limiting illnesses that a clinician recognises from the morphology and the story, treats supportively, and uses as a chance to find and protect the vulnerable contact. This page owns the two flagship benign exanthems that do not have their own dedicated leaves — roseola (HHV-6 and HHV-7) and erythema infectiosum (parvovirus B19) — together with the reasoning that separates them from their dangerous mimics. Measles, rubella, varicella, hand-foot-and-mouth disease, Kawasaki disease and staphylococcal scalded skin syndrome each have their own pages; this one teaches you how to point a febrile rash towards the benign answer and, just as importantly, when to point it away. [1] [8]
References10ShowHide
- [1]Young NS; Brown KE Parvovirus B19. N Engl J Med, 2004.PMID 14762186
- [2]Heegaard ED; Brown KE Human parvovirus B19. Clin Microbiol Rev, 2002.PMID 12097253
- [3]Enders M; Klingel K; Weidner A; Baisch C; Kandolf R; Schalasta G; Hentschel R; Jilg W; Modrow S Risk of fetal hydrops and non-hydropic late intrauterine fetal death after gestational parvovirus B19 infection. J Clin Virol, 2010.PMID 20729141
- [4]Frickhofen N; Abkowitz JL; Safford M; Berry JM; Antunez-de-Mayolo J; Astrow A; Cohen R; Halperin I; King L; Mintzer D; et al Persistent B19 parvovirus infection in patients infected with human immunodeficiency virus type 1 (HIV-1): a treatable cause of chronic anemia in AIDS. Ann Intern Med, 1990.PMID 2173460
- [5]Yamanishi K; Okuno T; Shiraki K; Takahashi M; Kondo T; Asano Y; Kurata T Identification of human herpesvirus-6 as a causal agent for exanthem subitum. Lancet, 1988.PMID 2896909
- [6]Hall CB; Long CE; Schnabel KC; Caserta MT; McIntyre KM; Costanzo MA; Knott A; Dewhurst S; Insel RA; Epstein LG Human herpesvirus-6 infection in children. A prospective study of complications and reactivation. N Engl J Med, 1994.PMID 8035839
- [7]Zerr DM; Meier AS; Selke SS; Frenkel LM; Huang ML; Wald A; Rhoads MP; Nguy L; Bornemann R; Morrow RA; Corey L A population-based study of primary human herpesvirus 6 infection. N Engl J Med, 2005.PMID 15728809
- [8]Tesini BL Clinical impact of primary infection with roseoloviruses. Curr Opin Virol, 2014.PMID 25462439
- [9]Hall CB; Caserta MT; Schnabel KC; Boeckh M; Carnahan JA; Petheram L; Shelley GA; Dewhurst S Characteristics and acquisition of human herpesvirus (HHV) 7 infections in relation to infection with HHV-6. J Infect Dis, 2006.PMID 16544246
- [10]Caserta MT; Hall CB; Schnabel K; McIntyre K; Long C; Costanzo M Primary human herpesvirus 7 infection: a comparison of human herpesvirus 7 and human herpesvirus 6 infections. J Pediatr, 1998.PMID 9738722