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Rickettsialpox in Adult
Other Resources UpToDate PubMed

Rickettsialpox in Adult

Contributors: Edith Lederman MD, Noah Craft MD, PhD
Other Resources UpToDate PubMed


Rickettsialpox is a febrile, infectious disease caused by Rickettsia akari, which is transmitted to humans by the painless bite of mouse mites.

The disease has been identified in urban areas of the United States as well as South Korea, South Africa, and parts of Russia.

The bite follows a 10- to 24-day incubation period, after which an eschar at the site of the mite bite appears (1 of 7 patients will have multiple eschars), followed by fever, nontender regional lymphadenopathy, headache, photophobia, and anorexia 2 to 7 days later. The clinical course of the disease lasts 2 to 3 weeks and is generally self-limited. A persistent headache and lassitude can last for weeks following the acute illness. No deaths clearly attributable to rickettsialpox have been reported to date.


A79.1 – Rickettsialpox due to Rickettsia akari

75096007 – Rickettsialpox

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Differential Diagnosis & Pitfalls

  • Other rickettsioses with eschar that are typically acquired outside the United States (eg, tick typhus, Mediterranean spotted fever, and Scrub typhus).
  • Varicella lesions (primary or post-vaccination) evolve in different stages (ie, they do not appear uniform) and often scar, whereas rickettsialpox lesions do not.
  • Eczema herpeticum
  • Eczema vaccinatum vaccinia
  • Disseminated gonorrhea
  • Mpox
  • Enteroviral infection
  • Mononucleosis
  • Cutaneous anthrax
  • Spider bite
  • Acute meningococcemia (early)
  • The lesions of Smallpox are deeper and larger and are prominent on the face (this has been eradicated but remains a bioterrorism threat).

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Last Updated:09/05/2023
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Rickettsialpox in Adult
A medical illustration showing key findings of Rickettsialpox : Fever, Headache, Bite or trauma site, Eschar, Mouse exposure, Smooth papules
Clinical image of Rickettsialpox - imageId=167281. Click to open in gallery.  caption: 'An eschar with a surrounding erythematous plaque on the leg.'
An eschar with a surrounding erythematous plaque on the leg.
Copyright © 2024 VisualDx®. All rights reserved.