Herpes simplex

Last author update: 1 September 2011
Last staff update: 22 December 2020

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PubMed search: herpes simplex [title] pneumonia

Elliot Weisenberg, M.D.
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Cite this page: Weisenberg E. Herpes simplex. website. Accessed September 26th, 2023.
Definition / general
  • Herpes simplex virus (HSV), serotypes HSV-1 and HSV-2, cause acute infection followed by latent phase that may reactivate to infectious form
  • See also Skin - nontumor chapter
  • HSV-1 and HSV-2 are alpha group herpes viruses with similar genotypes but serologic differences; may both infect the lung
  • HSV-1 usually affects oral pharynx; HSV-2 usually causes genital infection
  • Virus spreads via sensory neurons where latent infection is established
  • Reactivation may be symptomatic or asymptomatic, virus spreads via nerves to mucus membranes or skin, where it replicates
  • Newborns (see below), patients with impaired mucosal defenses, burn patients, trauma patients, and severely immunocompromised patients are at greatest risk
  • Also associated with coexisting bacterial pneumonia (J Crit Care 2011;26:432.e1)
  • Also be caused by intubation of patient with active oral disease
  • Immunostains, PCR, culture or electron microscopy can confirm the diagnosis if necessary
Gross description
  • Diffusely firm lungs with small yellow / red necrotic areas
Gross images

Contributed by Yale Rosen, M.D.
Various images Various images

Various images

Microscopic (histologic) description
  • Interstitial pneumonia with necrosis of bronchial and alveolar epithelium and acute and chronic inflammatory infiltrate
  • Occasional intranuclear viral inclusions at edge of necrotic areas
  • Neutrophilic infiltrates may resemble bacterial bronchopneumonia, but Cowdry type A or B nuclear inclusions are generally diagnostic
Microscopic (histologic) images

Images hosted on other servers:
Immunostain highlights<br>HSV+ cell in<br>broncheo-alveolar lavage

Immunostain highlights
HSV+ cell in
broncheo-alveolar lavage

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