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.
Rickettsialpox in Adult
Alerts and Notices
Synopsis
Codes
ICD10CM:
A79.1 – Rickettsialpox due to Rickettsia akari
SNOMEDCT:
75096007 – Rickettsialpox
A79.1 – Rickettsialpox due to Rickettsia akari
SNOMEDCT:
75096007 – Rickettsialpox
Look For
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Diagnostic Pearls
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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
- Gonococcemia
- Monkeypox
- Enteroviral infections
- Infectious 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).
Best Tests
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Management Pearls
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Therapy
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References
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Last Updated:05/30/2022
Rickettsialpox in Adult