roseola infantum

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Roseola infantum Prof. Saad S Al Ani

Prof.Saad S Al AniSenior Pedaitric Consultant Head of pedaitric DepartmentKhorfakkan HospitalSharjah ,UAE

Roseola infantum



Roseola is a mild febrile, exanthematous illness occurring almost exclusively during infancy

Roseola Infantum

(exanthem subitum, or sixth disease )

More than 95% of roseola cases occur in children younger than 3 yr, with a peak at 6-15 mo of age




Roseola Infantum (cont.)

(exanthem subitum, or sixth disease )

Transplacental antibodies likely protect most infants until 6 mo of age.

Infants with classic roseola exhibit a unique constellation of findings displayed over a short period of time




Etiology

Human herpesvirus 6 (HHV-6) is the etiologic agent for most cases of and human herpesvirus 7 (HHV-7) is in some cases of roseola

HHV-6 and HHV-7 belong to the β-herpesvirus subfamily of herpesviruses



Etiology (cont.)

The principal target cells for HHV-6 and HHV-7 infection in vivo are CD4 T cells

HHV-6 can also infect other cells, including : CD8 (suppressor) T cells, natural killer T cells, δγ T cells, glial cells, epithelial cells, monocytes, megakaryocytes, and endothelial cells


Roseola infantum Prof. Saad S Al AniRoseola infantum Prof. Saad S Al Ani

Epidemiology

Primary HHV-6 infection occurs early in life.

More than 90% of newborn infants are HHV-6 seropositive, reflecting transplacental transfer of maternal antibodies.



Epidemiology (cont.)

By 4-6 mo of age, the prevalence drops significantly (0-60%).

By 12 mo of age, 60-90% of children possess antibodies to HHV-6,




By 3-5 yr, 80-100% of children are seropositive.

Peak acquisition of primary HHV-6 infection, from 6-15 mo of age, corresponds with peak acquisition of roseola.




Less than half of HHV-6 infections in U.S. infants are clinically recognizable as roseola,

Primary infection with HHV-7 occurs slightly later than HHV-6 infection, with 45-75% of children infected by 2 yr of age and 90% by 7-10 yr of age

whereas 80% of Japanese infants with primary HHV-6 infection develop roseola.




Roseola can develop in children year-round

A higher incidence during spring and fall months




Children with roseola rarely report contact with other affected children

Outbreaks are uncommon.



The incubation period averages 10 days (range of 5-15 days).


Sex, race, and geography ,do not play an important role in acquisition of roseola.



Pathogenesis

Virus is probably acquired from the saliva of healthy persons and enters the host through the oral, nasal, or conjunctival mucosa.

Cellular receptors for both viruses have been identified: * HHV-6 uses the CD46 receptor * HHV-7 uses the CD4 receptor

Both viruses may evade the immune system through downregulation of the major histocompatibility complex (MHC) type I response



Clinical ManifestationsInfants with classic roseola exhibit a unique constellation of findings displayed over a short period of time.

The prodromal period is usually asymptomatic but may include mild upper respiratory tract signs, among them: * minimal rhinorrhea*slight pharyngeal inflammation* mild conjunctival redness.



Clinical Manifestations (Cont.)

Mild cervical or, less frequently, occipital lymphadenopathy may be noted

Some children may have mild palpebral edema




Physical findings during the prodromal stage may simply reflect an accompanying respiratory viral infection.

Clinical illness is generally heralded by high temperature usually ranging from 37.9 to 40°C (101-106°F), with an average of 39°C (103°F).




Some children may become irritable and anorexic during the febrile stage, but most behave normally despite high temperatures.

Seizures may occur in 5-10% of children with roseola during this febrile period. Infrequent complaints include: * rhinorrhea*sore throat* abdominal pain, vomiting, and diarrhea .




In Asian countries, ulcers at the uvulopalatoglossal junction (Nagayama spots) are common in infants with roseola.

Fever persists for 3-5 days, and then typically resolves rather abruptly ("crisis").

A rash appears within 12-24 hr of fever resolution



Clinical signs associated with primary HHV-6 infection and the proportion of children with primary HHV-6 infection manifesting each

sign as documented by both viremia and seroconversion in 335

children studied in Rochester, NY.



In patients with primary HHV-6 infection, the mean total white blood cell (WBC) and lymphocyte counts are shown by day of illness in relation to

the average course of fever

Pruksananonda P, Hall C, Insel R, et al. Primary human herpesvirus 6

infection in young children. N Engl J Med 1992;326:1445–1450.)



Exanthems associated with roseola



The rash

In many cases, the rash develops during defervescence or within a few hours of fever resolution.

The rash of roseola is rose colored and is fairly distinctive



The rash (cont.)

it may be confused with exanthems resulting from rubella, measles, or erythema infectiosum

The roseola rash begins as discrete, small (2-5 mm), slightly raised pink lesions on the trunk and usually spreads to the neck, face, and proximal extremities



The rash (cont.)

The rash is not usually pruritic, and no vesicles or pustules develop

Lesions typically remain discrete but occasionally may become almost confluent

After 1-3 days, the rash fades



Subtle differences in clinical presentation

In roseola associated with HHV-7 Subtle differences in clinical presentation compared with HHV-6 cases include : 1. Slightly older age 2. Lower mean temperature 3. Shorter duration of fever

These differences are insufficient to clinically distinguish HHV-6- from HHV-7-associated roseola



LABORATORY FINDINGS

By the time the exanthem appears, the WBC count falls to 4,000-6,000 WBCs/μL with a relative lymphocytosis (70-90% )

White blood cell (WBC) counts of 8,000-9,000 WBCs/μL

may be found during the first few days of fever in children

with roseola



LABORATORY FINDINGS (cont.)

The cerebrospinal fluid from rare cases of HHV-6-associated meningoencephalitis and encephalitis is characterized by: * mild pleocytosis with predominance of mononuclear cells * normal glucose * normal to slightly elevated protein.

The cerebrospinal fluid in children with HHV-6-associated febrile seizures typically is normal



DIFFERENTIAL DIAGNOSIS

1.Rubella

2.Measles

3.roseola-like illnesses i.e. Enteroviruses

4.Scarlet fever

5.Drug hypersensitivity



Treatment

The generally benign nature of roseola precludes consideration of antiviral therapy

Children with neurologic complications of roseola or immunocompromised children with severe HHV-6 or HHV-7 infection may address the need for specific antiviral therapy

Children in the febrile, pre-eruptive phase of roseola usually are quite comfortable and require little supportive therapy



Treatment (Cont.)

Adequate fluid balance should be maintained in all affected children

Those children who are uncomfortable and irritable, or in whom histories of febrile convulsions exists, may benefit from treatment with acetaminophen or ibuprofen.



Prognosis

The prognosis for the great majority of children with roseola is excellent, with no obvious sequelae

Damage resulting from direct viral invasion of the brain, liver, and other organs has been demonstrated for HHV-6

Deaths directly attributable to HHV-6 have been reported in normal as well as immunocompromised patients in whom encephalitis, hepatitis, pneumonitis, disseminated disease, or hemophagocytosis syndrome developed.



References• Caserta MT, Mock DJ, Dewhurst S: Human herpesvirus 6. Clin Infect Dis

2001;33:829-33. Medline Similar articles • Chua KB, Lam SK, AbuBakar S, et al: The predictive value of uvulo-

palatoglossal junctional ulcers as an early clinical sign of exanthem subitum due to human herpesvirus 6. J Clin Virol 2000;17:83-90. Medline Similar articles

• Desachy A, Ranger-Rogez S, Francois B, et al: Reactivation of human herpesvirus type 6 in multiple organ failure syndrome. Clin Infect Dis 2001;32:197-203. Medline Similar articles

• Leach CT: Human herpesvirus-6 and -7 infections in children: Agents of roseola and other syndromes. Curr Opin Pediatr 2000;12:269-74. Medline Similar articles

• Leach CT, Pollock BH, McClain KL, et al: Human herpesvirus 6 (HHV-6) and cytomegalovirus (CMV) infections in children with acquired immunodeficiency syndrome (AIDS) and cancer. Pediatr Infect Dis J 2002;21:125-32. Medline Similar articles

• Mendez JC, Dockrell DH, Espy MJ, et al: Human ß-herpesvirus interactions in solid organ transplant recipients. J Infect Dis 2001;183:179-84. Medline Similar articles

roseola infantum

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