viral exanthems

Angad, JaL

(MEASLES)

Etiology RNA virus of the genus Morbillivirus in the

family ParamyxoviridaeEpidemiology

Prior to use of vaccine, peak incidence was among 5-10 y/o

Transmission 90% of susceptible contacts acquire the

disease Maximal dissemination occurs by droplet

spray during the prodromal period

Incubation Period: Last 10-12 daysProdromal stage: Last 3-5 days

characterized by low-mod grade fever, dry cough , coryza, photophobia & conjunctivitis. Kopliks spots appear by 2nd -3rd day

Rash - as exanthem progresses systemic symptoms subside

Self-limited infection in most patients Complications common in malnourished

children, the unimmunized & those w/ congenital immunodeficiency,and leukemia

Acute complications: otitis media, pneumonia (Hecht giant cell pneumonia), diarrhea, measles encephalitis, thrombocytopenia.

Chronic complication: subacute sclerosing panencephalitis.

Based on Clinical pictureLaboratory confirmation is rarely needed

Measles IgM – detectable for 1 month after the illness but sensitivity is limited

Prevention – MMR Acute Infection – treatment is

entirely supportive (antipyretics, bed rest, adequate fluid intake)

Secondary Bacterial Infection – administration of appropriate antibiotics

(GERMAN MEASLES / 3 DAYS MEASLES)

Common benign childhood infection manifested by a characteristic exanthem and lymphadenopathy

Etiology: RNA virus , genus Rubivirus, family Togaviridae

Epidemiology Humans are the only natural host of Rubella

virus Spread by oral droplet or transplacentally to

the fetus Peak incidence is 5-14 y/o

Pathogenesis: Not well understood

Incubation Period: 14 to 21 days.Prodromal phase

Mild catarrhal symptoms In adolescents and young adults: anorexia,

malaise, conjunctivitis, headache, low-grade fever, mild URT symptoms.

Retroauricular, post cervical & postoccipital lymphadenopathy

An enanthem appears just before the onset of the rash (FORCHHEIMER SPOTS)

• Skin Lesions• Petechiae on soft palate

• Enlarged lymph nodes

Maybe apparent from clinical symptoms and PE

Usually confirmed by serology or viral culture

Latex agglutination, enzyme immunoassay & fluorescent immunoassay

In most persons, rubella is mild Pregnant women infected during the 1st

trimester can pass the infection transplacentally

Congenital rubella syndrome Congenital heart defects Cataracts Microphthalmia Deafness Microcephaly Hydrocephaly

Prevention – MMR Pregnant women should not be given live rubella virus vaccine and should avoid becoming pregnant for 3 mo after they have been vaccinated

Acute Infection – symptomatic

FIFTH DISEASE

EI is a childhood exanthem occurring with primary parvovirus B19 infection

Characterized by edematous erythematous plaques on the cheeks (“slapped cheeks”) and an erythematous lacy eruption on the trunk and extremities

Transmission: Spreads via droplet aerosol

Incubation Period: 7 to 28 daysChildren: Fever, malaise, headache,

coryza. Headache, sore throat, fever, myalgias, nausea, diarrhea, conjunctivitis, cough may coincide with rash.

Adults: Constitutional symptoms more severe, with fever, adenopathy, arthritis/arthralgias involving small joints of hand, knees, wrists, ankles, feet. Numbness and tingling of fingers.

Diffuse erythema and edema of the cheeks with “slapped cheek” facies in a child

Usually based on clinical presentation of the typical rash

Serologic test for B19PCR, nucleic acid hybridization

“Slapped cheeks” lesions fade over 1 to 4 days. Eruption lasts for 5-9 days but can recur

Arthralgia is self-limited In patients w/ chronic hemolytic

anemias transient aplastic may occur Fetal B19 infection may be

complicated by nonimmune fetal hydrops secondary to infection of erythroid precursors

No specific antiviral therapy

IVIG have been used to treat episodes of anemia and bone marrow failure

EXANTHEM SUBITUM

Exanthema subitum (sudden rash) is associated with primary HHV-6 and HHV-7 infection, characterized by the sudden appearance of rash as high-fever lysis in a healthy-appearing infant

Primary infection is acquired via oropharyngeal secretions

Pathogenesis of ES rash is not known

Incubation period: 7 -17 daysHigh fever with morning remission

until the 4th day when it falls to normal coincident with the appearance of rash

Infant remarkably well despite high fever

In Asian countries, ulcers at the uvulo-palatoglossal junction (NAGAYAMA SPOTS) are common.

Multiple, blanchable macules and papules on the back of a febrile child, which appeared as the temperature fell

Based on age, history and PE findings

Serology, virus culture, Antigen detection and PCR

Self-limited with rare sequelae

High fever maybe associated w/ seizures

HHV-6 & HHV-7 persist throughout the life of the patient

Treatment is supportive (antipyretics, bed rest, adequate fluid intake)

RUBEOLA RUBELLA ROSEOLA

ERYTHEMA INFECTIOS

UM

Etiology Paramyxoviridae Togaviridae Virus (prob) Virus (prob)

Incubation Period

10 – 12 14 - 21 7 - 17 7 - 28

Epid All ages 6 -18 months All ages Rarely > 3 y/o

Rash Maculopapular Maculopapular Maculopapular Maculopapular

Distribution Begins face, spread rapidly

Begins trunk → arms & neck face- legs – 3d

Last for 24 hr ….

Prodrome 3 – 5 d low-mod fever, hackhing cough, coryza, conjunctivitis, kopliks after 2-3 days

Mild catarrhal , retroauricular, post cervical, post occipital lymphadenopathy

None None

RUBEOLA

RUBELLA ROSEOLA

ERYTHEMA INFECTIOSUM

Fever pattern

↑ T abruptly as rash appears ↓ T when rash reaches legs & feet

Sudden onset ↑ T ↓ T on 3rd-4th d as rashes appear

Absent or low grade

Infectivity

Isolate- 7th d post exposure unti l 5 d after rash appeared

9th – 10th d post exposure (peak)

3rd day of fever and 1st day of rash

Rash Lateral neck, ears, hairline → back, abdomen, thigh → feet on 2nd

Absence of PE findings to explain fever , trunk and extremities

Rash 3 stages1.Slapped cheek2.Maculopapular on 3rd as face fades3.Lacy or reticulated appearance rash – fades central clearing pruritic lasts 2-39 days