This document summarizes several viral exanthems (diseases that cause rashes), including measles, varicella-zoster, herpes simplex, and rubella. Measles is highly contagious and causes a rash that starts on the face and spreads downward over 3 days. Varicella-zoster causes chickenpox (varicella) in children and shingles (zoster) reactivation in adults. Herpes simplex causes lesions around the mouth, genitals or other areas that can reactivate. Rubella typically causes a rash on the face and spreads downward over 3 days and can cause birth defects if contracted during pregnancy.

1. Viral exanthems
Characteristic rash

2. Measles (Rubeola)
 A RNA virus causing acute febrile eruption
 Found only in humans
 Transmission by nasopharyngeal secretions
 Highly contagious, with ~90% secondary
attack rate
 Virus grows in respiratory epithelium &
spreads by blood
 Incubation period- ~10 days

3. Clinical features
 Initially high-grade fever, malaise, dry
cough, nasal discharge
 Erythematous maculopapular rash after ~1
week
 Koplik’s spots on oral mucosa
 Rash starts from forehead, and spreads downwards
 Resolution in same order over 3 days
 Complications-
 Viral or secondary bacterial pneumonia
 Myocarditis, hepatitis, keratitis
 Encephalomyelitis
 Subacute sclerosing pan-encephalitis (SSPE)- rare, late

4. Management
 Dx-
 Clinical
 Leukopenia
 Measles virus/Ag in respiratory secretions/urine
 Treatment- supportive
 Prevention-
 Passive immunization with immunoglobulin
 Active immunization with vaccine

5. Varicella-zoster
 A DNA virus
 Man is only reservoir
 Transmission- respiratory secretions-?
 Highly contagious, >90% secondary attack
rate
 Incubation period- ~2 weeks
 Causes-
 Varicella/chicken-pox- primary infection- children
 Zoster- reactivation- elderly/immunocompromised

6. Clinical features
 Varicella- lasts ~7 days
 Fever, malaise
 Rash- erythematous macules, papules, vesicles, scabs
in various stages of evolution simultaneously
 First on face & trunk, then spreads
 Complication- secondary bacterial infection, pneumonia,
hepatitis, ataxia, meningitis, myelitis
 Herpes zoster- lasts ~7 days
 Reactivation of virus from dorsal root ganglia
 U/L dermatomal severe pain, followed by vesicular eruption
 Complication- post-herpetic neuralgia, meningoencephalitis

7. Management
 Dx-
 Clinical
 Tzanck smear- multinucleated giant-cell
 Isolation of virus in tissue culture
 Rising Ab titres
 Rx-
 Supportive
 Acyclovir- oral/IV
 Steroids & neuropathic analgesics for neuralgia
 Prevention-
 Passive immunoglobulins
 Active vaccine

8. Herpes simplex
 A ds-DNA virus
 HSV-1- oral, HSV-2- genital
 Transmission- by direct contact,
genital herpes considered a STD
 Incubation period- ~1 week
 Initial exposure- local viral replication
 Through peripheral nerves, virus reaches ganglia
 Replicates in ganglia & spreads centrifugally to skin via
peripheral sensory nerves
 Reactivation- with stress, trauma, immunosuppression

9. Clinical features
 Initial disease more symptomatic than
recurrences
 Fever, malaise, myalgia; with painful
vesicular eruption & regional LNE
 Herpes labialis/orofacial/gingivostomatitis
 Herpes genitalis
 Herpetic whitlow- fingers
 Herpetic keratoconjunctivitis
 Herpes encephalitis

10. Management
 Dx-
 Clinical
 DFA
 Biopsy
 IgG HSV test
 Rx- topical/oral Acyclovir; reduce frequency,
duration, severity; NOT CURATIVE
 Prevention-
 Barrier- condom
 Prophylactic Acyclovir

11. Rubella- German measles
 Caused by Rubella virus (RNA)
 Incubation period- ~2-3 weeks
 A benign febrile viral disease with LNE
 Rash- discrete maculopapular rash,
starts on forehead & face and spread down
 Rash typically lasts for ~3 days
 Prevention- live attenuated vaccine,
specially to prevent congenital rubella

12. Congenital rubella
 Consists of-
 Cardiac malformation- PDA, VSD, PS
 Eye lesions- clouded cornea, cataract, chorioretinitis
 Microcephaly
 Mental retardation
 Deafness
 Expanded rubella syndrome-
 Purpura, HSmegaly, IUGR, pneumonitis, myocarditis
 Late complications-
 DM, subacute panencephalitis