Eschar: A Stepping Stone to Scrub Typhus

Abstract

A 9-year-old girl with a 5-day history of fever and headache presented to our emergency department. She did not report rhinorrhea, cough, abdominal pain, vomiting, or diarrhea. Physical examination revealed bilateral neck lymphadenopathy and nonpruritic macular rashes over her trunk and arms (Figure 1; available at www.jpeds.com). A painless papule was located on the buttock and eschar was diagnosed (Figure 2). Blood tests showed thrombocytopenia and elevated liver function (platelet count: 62 000/µL; aspartate transaminase: 297 U/L; and alanine transaminase: 295 U/L). The patient was admitted and doxycycline was applied under the suspicion of scrub typhus. Defervescence occurred the next day, and she was discharged 3 days later. The eschar changed color to black and sloughed off 5 days later (Figure 3; available at www.jpeds.com). The diagnosis of scrub typhus was confirmed by an immunofluorescence test 1 week later performed by the Centers for Disease Control in Taiwan. Scrub typhus is a zoonotic rickettsial disease caused by Orientia tsutsugamushi and is endemic to Southeast Asia. It is transmitted to humans after a bite by a chigger and is estimated to infect 1 million cases per year worldwide.1Rosenberg R. Drug-resistant scrub typhus: paradigm and paradox.Parasitol Today. 1997; 13: 131-132Abstract Full Text PDF PubMed Scopus (75) Google Scholar The diagnosis of scrub typhus remains a challenge to physicians for its protean manifestations, and the mortality of untreated patients is high (0%-70%).2Taylor A.J. Paris D.H. Newton P.N. A systematic review of mortality from untreated scrub typhus (Orientia tsutsugamushi).PLoS Negl Trop Dis. 2015; 9: e0003971Google Scholar Once the preemptive diagnosis is established and empirical antibiotics with doxycycline or azithromycin are administered, dramatic clinical improvement is achieved. The incubation period is approximately 6-20 days; therefore, a travel history to the rural areas of Southeast Asia is easily missed.2Taylor A.J. Paris D.H. Newton P.N. A systematic review of mortality from untreated scrub typhus (Orientia tsutsugamushi).PLoS Negl Trop Dis. 2015; 9: e0003971Google Scholar, 3Jim W.T. Chiu N.C. Chan W.T. Ho C.S. Chang J.H. Huang S.Y. et al.Clinical manifestations, laboratory findings and complications of pediatric scrub typhus in Eastern Taiwan.Pediatr Neonatol. 2009; 50: 96-101Abstract Full Text PDF PubMed Scopus (27) Google Scholar Skin rash is presented in approximately 50% of patients with scrub typhus, but is nonspecific.3Jim W.T. Chiu N.C. Chan W.T. Ho C.S. Chang J.H. Huang S.Y. et al.Clinical manifestations, laboratory findings and complications of pediatric scrub typhus in Eastern Taiwan.Pediatr Neonatol. 2009; 50: 96-101Abstract Full Text PDF PubMed Scopus (27) Google Scholar Laboratory tests, such as serology, are time consuming, but rapid tests are not available widely. The presence of eschar is highly diagnostic and serves as a stepping stone to scrub typhus and provides a clue for early successful empirical treatment.3Jim W.T. Chiu N.C. Chan W.T. Ho C.S. Chang J.H. Huang S.Y. et al.Clinical manifestations, laboratory findings and complications of pediatric scrub typhus in Eastern Taiwan.Pediatr Neonatol. 2009; 50: 96-101Abstract Full Text PDF PubMed Scopus (27) Google Scholar, 4Sarthak S. Samprathi M. Fever, hepatosplenomegaly, and a typical skin lesion.J Pediatr. 2016; 169 (e1): 321Abstract Full Text Full Text PDF PubMed Scopus (1) Google Scholar Eschar is noted in 40%-60% of patients, and the location is commonly covered by clothes.5Rose W. Rajan R.J. Punnen A. Ghosh U. Distribution of eschar in pediatric scrub typhus.J Trop Pediatr. 2016; 62: 415-420Crossref PubMed Scopus (19) Google Scholar Therefore, detailed history taking and careful physical examination contribute to early diagnosis and prompt treatment. Figure 3The eschar became mature and changed color to black 5 days later. It sloughed off later.View Large Image Figure ViewerDownload Hi-res image Download (PPT)