What are the signs and symptoms of scrub typhus?

Updated: Apr 19, 2018
  • Author: David J Cennimo, MD, FAAP, FACP, FIDSA, AAHIVS; Chief Editor: Russell W Steele, MD  more...
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Elements brought out in the history may include the following:

  • Travel to an area where scrub typhus is endemic

  • Chigger bite (often painless and unnoticed)

  • Incubation period of 6-20 days (average, 10 days)

  • Headaches, shaking chills, lymphadenopathy, conjunctival injection, fever, anorexia, and general apathy

  • Rash; a small, painless, gradually enlarging papule, which leads to an area of central necrosis and is followed by eschar formation

Although many other conditions can present with a high fever, the presentation of the rash, a history of exposure to endemic areas, and the presentation of the sore caused by the bite can be diagnostic of scrub fever.

Physical findings may include the following:

  • Site of infection marked by a chigger bite

  • Eschar at the inoculation site (in about 50% of patients with primary infection and 30% of those with recurrent infection)

  • High fever (40-40.5°C [104-105°F]), occurring more than 98% of the time

  • Tender regional or generalized lymphadenopathy, occurring in 40-97% of cases

  • Less frequently, ocular pain, wet cough, malaise, and injected conjunctiva

  • Centrifugal macular rash on the trunk

  • Enlargement of the spleen, cough, and delirium

  • Pneumonitis or encephalitis

  • Central nervous system (CNS), pulmonary, or cardiac involvement

  • Rarely, acute renal failure, shock, and disseminated intravascular coagulation (DIC)

See Presentation for more detail.

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