Viral Exanthems: Cutaneous manifestions of viral
infection

1) result of viral replication in the epidermis - direct effect of viral replication


2) secondary effect of viral replication elsewhere in the body - host response to the virus


Clinical manifestations

Vesicles
Macules
Papules

Generally are non-specific
Consider systemic manifestations simultaneously

Vesicles: HSV-1, HSV-2
VZV
Poxviruses
Coxsackie viruses

Macules: Rubella
EBV
HHV-6
Coxsackie, echovirus

Macules and papules
Measles
Echovirus
Parvovirus B19

Diagnosis
· Culture
· Microscopic examination of infected tissue
· Detection of viral antigens
· Detection of viral nucleic acid
· SerologyPathophysiology

Affect skin by:
§ Direct inoculation
· Papilloma
· Poxviruses
· Primary HSV

§ Local spread from an internal source
· Recurrent VZV, HSV

§ Systemic infection
· Primary VZV

Herpes simplex viruses 1 and 2

Most commonly known for cold sores and genital herpes

Primary mucocutaneous infection followed by a latent infection in the neuronal ganglia

Recurrent disease with viral reactivation with subsequent active mucocutaneous infections


Orolabial herpes - >90 HSV-1, usually acquired early in life

Primary infection - gingivostomatitis
Peaks between 1 and 5 years of age
Sore throat, regional lymphadenopathy, fever and widespread painful ulcerations of the oral cavity and lips

90% of adults have evidence of HSV-1 infection

Recurrent episodes

Treatment - acyclovir

Complications - encephalitis

Varicella Zoster virus

Primary varicella - chicken pox
Recurrent varicella - herpes zoster (shingles)

Primary infection:
Children - onset of rash, low-grade fever, malaise
Adults - prodromal symptoms of headache, myalgia, nausea and vomiting
Followed by the development of the rash

Skin lesions - erythematous macules that progress to papules, vesicules pustules and crusts
Predominantly seen centrally and on proximal extremities

Complications of VZV infection:
CNS involvement, pneumonia or varicella hepatitis in adults and immunocompromised individuals

Reactivation - post-herpetic neuralgia

Vaccine - live attenuated vaccine

Treatment - acyclovir

Measles (rubeola)

Most prevalent in children 5-10 years of age
Seen predominantly in the winter and spring
Spread via respiratory secretions

Disease progression:
Incubation
Prodrome
High fever, cough, coryza, conjunctivitis, malaise and Koplik's spot on the buccal mucosa. Image of Koplik's spots.


Development of the rash - erythematous macular and popular rash on face, neck, trunk and extremities

Rash: virus-antibody complexes

Complications of measles virus infection:
Uncommon - encephalitis, purpura
Rare - subacute sclerosing panencephalitis
Occurs years later, replicating virus in the brain,
fatal

Atypical measles - seen in people previously given a killed measles virus vaccine and then become infected with wild type measles

Prevention: live attenuated measles vaccine

Measles and Traveling

Rubella (German measles, 3 day measles)
Mild disease
Disease progression:
Incubation period (14-21 days)
Prodrome
Low-grade fever, headache, conjunctivitis, cough, sore throat, lymphadenopathy and arthritis in adults
Rash - erythematous macular rash on face spreading to the trunk and extremities
Ab-Ag complexes

Complications
Rare in adults and children
Congenital malformation in 50% of infected neonates
Prevention of rubella virus infection
Live attenuated vaccine

Diagnosis:
Serology, Viral antigens

Other viruses that cause similar symptoms:
Coxsackie virus
EBV
Arboviruses