eMedicine Specialties > Infectious Diseases > Bacterial Infections

Rickettsialpox

Author: Julie A Ake, MD, Fellow, Infectious Disease Service, Walter Reed Army Medical Center
Coauthor(s): Richard J Scarfone, MD, Associate Professor, Department of Pediatrics, University of Pennsylvania School of Medicine; Attending Physician and Director of Emergency Preparedness, Division of Emergency Medicine, The Children's Hospital of Philadelphia; Timothy J Whitman, DO, Consulting Staff, Department of Infectious Disease, National Naval Medical Center; Chi Hiong U Go, MD, Assistant Professor, Department of Internal Medicine, Texas Tech University Health Science Center at Odessa
Contributor Information and Disclosures

Updated: Apr 11, 2008

Introduction

Background

Rickettsialpox is a mild, self-limited, zoonotic febrile illness characterized by eschar formation at the location of a mite bite, followed by the onset of systemic symptoms and a more generalized papulovesicular rash. The causative agent is Rickettsia akari, a member of the spotted-fever group of rickettsiae.

Pathophysiology

R akari is an obligate intracellular gram-negative coccobacillus. Its vector is the colorless mite Liponyssoides sanguineus (formerly Allodermanyssus sanguineus), which is found on mice (most commonly the house mouse [Mus musculus]) and other rodents. These hosts serve as the reservoir for the disease. A sanguineus will bite humans when murine hosts are scarce. About 7-10 days after the painless bite, a papular skin lesion appears at the bite location and becomes vesicular with a surrounding area of erythema. An eschar forms and slowly heals. About 3-7 days after the initial skin lesion develops, patients may suddenly develop high-grade fever, chills, headaches, and myalgias with subsequent development of a sparse generalized papulovesicular rash.

The disease is mild and self-limited and usually persists for about a week.

Frequency

United States

Rickettsialpox occurs primarily in urban areas, where the density of mites, mice, and humans is high. Huebner et al first isolated and named rickettsialpox in 1946 in New York City.1

Rickettsialpox has been reported primarily in the northeastern and midwest United States (Boston, Mass; West Hartford, Conn; Philadelphia, Pa; Pittsburgh, Pa; and Cleveland, Ohio). Cases have also been reported in North Carolina, Arkansas, and Utah.

Although the prevalence of confirmed cases is very low, several reports suggest the disease is more common than previously thought. Serologic evidence of rickettsialpox exposure was found in 16% of 631 intravenous drug users in inner-city Baltimore, Md, and in 9% of 204 intravenous drug users in Harlem, NY.2,3 In addition, between 2001 and 2003, the number of clinical samples submitted to the Centers for Disease Control and Prevention (CDC) increased following the anthrax bioterror attack, reflecting an increased awareness of eschar-associated febrile illness.4  Prior to this, these clinical syndromes may have been misdiagnosed, or perhaps the infected persons did not seek medical attention. Consequently, rickettsialpox is widely believed to be an underrecognized and underreported clinical entity.

International

Internationally, the disease has been described in South Africa, Costa Rica, France, Italy, Turkey, Croatia, the Ukraine, Russia, and Korea.

Mortality/Morbidity

Rickettsialpox is a benign, self-limited disease. No fatalities have been reported. The incubation period varies from 10-21 days. Rickettsialpox usually resolves within 14-21 days; however, headache and lassitude may persist for another 1-2 weeks.

Sex

Rickettsialpox has no sexual predilection.

Age

Rickettsialpox has no age predilection. It has been reported in patients aged 6 months to 72 years.

Clinical

History

  • Following a mite bite, R akari proliferates locally in the skin. After 7-10 days, a firm, red papule 1-1.5 cm in diameter appears; in a few days, it vesiculates with a surrounding area of erythema. The lesion then ulcerates, forms an eschar, and slowly heals.
  • About 3-7 days after the appearance of the skin lesion, rickettsialpox may manifest as a sudden onset of high fever, chills, sore throat, rigor and profuse sweating, myalgias (especially backache), anorexia, and photophobia. Untreated, fever may last a week. Vertigo, conjunctival injection, cough, rhinorrhea, nausea, and vomiting sometimes occur. Headaches and neck stiffness may be severe. Regional lymphadenopathy at the draining site of the eschar is common, and generalized lymphadenopathy has also been reported. Lymphangitis is not a feature of rickettsialpox.
  • Approximately 2-3 days after the onset of systemic symptoms, the generalized papulovesicular rash of rickettsialpox erupts. This can involves palms and soles and is occasionally accompanied by an oropharyngeal enanthem. This rash typically lasts a week.

Physical

  • Patients may have high fever fluctuating between 101-104ºF.
  • The maculopapulovesicular exanthema is usually comprised of 20-40 lesions but may range from 5-100.  
    • The lesions typically begin as papules with subsequent vesiculation, but may remain avesicular.
    • Lesions are usually scattered on the face, trunk, and extremities with no particular sequence of involvement. Patients may present with lesions on the tongue, buccal mucosa, and pharynx.
    • Lesions may also be present on palms and soles.
    • The lesions are typically asymptomatic but can be pruritic.
    • Rashes last a week. Scabs form but do not leave scars.
  • At the time of presentation, an eschar is present in at least 95% of affected individuals. The mite bite is painless and begins as an erythematous papule, which develops into a tense vesicle that ruptures to form a dark crust with surrounding induration. More than one eschar may be present.  
    • Mite bites can occur on any part of the body, including the hands, feet, face, and angle of the mouth (labial commissure). They do occur in covered areas.
    • Regional adenopathy may be present and is usually tender.

Causes

  • Rickettsialpox is caused by R akari and was first described in 1946.
  • Rickettsialpox is sporadically observed in many urban centers of the United States. The bloodsucking mite L sanguineus is the vector, and mice (typically M musculus) and other rodents are the reservoir.
  • When murine hosts are scarce, A sanguineus will bite humans.
  • No human-to-human transmission occurs.

More on Rickettsialpox

Overview: Rickettsialpox
Differential Diagnoses & Workup: Rickettsialpox
Treatment & Medication: Rickettsialpox
Follow-up: Rickettsialpox
References
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References

  1. Huebner RJ, Stamps P, Armstrong C. Rickettsialpox. A newly recognized rickettsial disease. 1. isolation of the etiological agent. Public Health Report. 1946;61:1605.

  2. Comer JA, Tzianabos T, Flynn C, Vlahov D, Childs JE. Serologic evidence of rickettsialpox (Rickettsia akari) infection among intravenous drug users in inner-city Baltimore, Maryland. Am J Trop Med Hyg. Jun 1999;60(6):894-8. [Medline].

  3. Comer JA, Diaz T, Vlahov D, Monterroso E, Childs JE. Evidence of rodent-associated Bartonella and Rickettsia infections among intravenous drug users from Central and East Harlem, New York City. Am J Trop Med Hyg. Dec 2001;65(6):855-60. [Medline].

  4. Paddock CD, Zaki SR, Koss T, Singleton J Jr, Sumner JW, Comer JA, et al. Rickettsialpox in New York City: a persistent urban zoonosis. Ann N Y Acad Sci. Jun 2003;990:36-44. [Medline].

  5. Anderson GW Jr, Osterman JV. Host defenses in experimental rickettsialpox: resistance of C3H mouse sublines. Acta Virol. Jun 1980;24(4):294-6. [Medline].

  6. Angeloni VL, Keller RA, Walker DH. Rickettsialpox-like illness in a traveler. Mil Med. Sep 1997;162(9):636-9. [Medline].

  7. Boyd AS. Rickettsialpox. Dermatol Clin. Apr 1997;15(2):313-8. [Medline].

  8. Brettman LR, Lewin S, Holzman RS, Goldman WD, Marr JS, Kechijian P, et al. Rickettsialpox: report of an outbreak and a contemporary review. Medicine (Baltimore). Sep 1981;60(5):363-72. [Medline].

  9. Heymann WR. Rickettsialpox. Clin Dermatol. May-Jun 1996;14(3):279-82. [Medline].

  10. Kass EM, Szaniawski WK, Levy H, Leach J, Srinivasan K, Rives C. Rickettsialpox in a New York City hospital, 1980 to 1989. N Engl J Med. Dec 15 1994;331(24):1612-7. [Medline].

  11. Kass EM, Szaniawski WK, Levy H, Leach J, Srinivasan K, Rives C. Rickettsialpox in a New York City hospital, 1980 to 1989. N Engl J Med. Dec 15 1994;331(24):1612-7. [Medline].

  12. Kemper CA, Spivack AP, Deresinski SC. Atypical papulovesicular rash due to infection with Rickettsia conorii. Clin Infect Dis. Oct 1992;15(4):591-4. [Medline].

  13. Kenyon RH, Pedersen CE Jr. Immune responses to Rickettsia akari infection in congenitally athymic nude mice. Infect Immun. May 1980;28(2):310-3. [Medline].

  14. Krinsky WL. Does epizootic lymphocytic choriomeningitis prime the pump for epidemic rickettsialpox?. Rev Infect Dis. Nov-Dec 1983;5(6):1118-9. [Medline].

  15. Krusell A, Comer JA, Sexton DJ. Rickettsialpox in North Carolina: a case report. Emerg Infect Dis. Jul 2002;8(7):727-8. [Medline].

  16. McDade JE, Black CM, Roumillat LF, Redus MA, Spruill CL. Addition of monoclonal antibodies specific for Rickettsia akari to the rickettsial diagnostic panel. J Clin Microbiol. Oct 1988;26(10):2221-3. [Medline].

  17. Myers SA, Sexton DJ. Dermatologic manifestations of arthropod-borne diseases. Infect Dis Clin North Am. Sep 1994;8(3):689-712. [Medline].

  18. Ozturk MK, Gunes T, Kose M, Coker C, Radulovic S. Rickettsialpox in Turkey. Emerg Infect Dis. Nov 2003;9(11):1498-9. [Medline].

  19. Paddock CD, Koss T, Eremeeva ME, Dasch GA, Zaki SR, Sumner JW. Isolation of Rickettsia akari from eschars of patients with rickettsialpox. Am J Trop Med Hyg. Oct 2006;75(4):732-8. [Medline].

  20. Paddock CD, Sumner JW, Comer JA, Zaki SR, Goldsmith CS, Goddard J, et al. Rickettsia parkeri: a newly recognized cause of spotted fever rickettsiosis in the United States. Clin Infect Dis. Mar 15 2004;38(6):805-11. [Medline].

  21. Paterson PY, Taylor W. Rickettsialpox. Bull N Y Acad Med. Jul 1966;42(7):579-87. [Medline].

  22. Radulovic S, Feng HM, Morovic M, Djelalija B, Popov V, Crocquet-Valdes P, et al. Isolation of Rickettsia akari from a patient in a region where Mediterranean spotted fever is endemic. Clin Infect Dis. Feb 1996;22(2):216-20. [Medline].

  23. Rickettsialpox. Lancet. Jan 16 1982;1(8264):148. [Medline].

  24. Saini R, Pui JC, Burgin S. Rickettsialpox: report of three cases and a review. J Am Acad Dermatol. Nov 2004;51(5 Suppl):S137-42. [Medline].

  25. Walker DH. Rickettsioses of the spotted fever group around the world. J Dermatol. Jun 1989;16(3):169-77. [Medline].

  26. Walker DH, Hudnall SD, Szaniawski WK, Feng HM. Monoclonal antibody-based immunohistochemical diagnosis of rickettsialpox: the macrophage is the principal target. Mod Pathol. May 1999;12(5):529-33. [Medline].

  27. Wong B, Singer C, Armstrong D, Millian SJ. Rickettsialpox. Case report and epidemiologic review. JAMA. Nov 2 1979;242(18):1998-9. [Medline].

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Further Reading

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Keywords

rickettsialpox, gamasid rickettsiosis, vesicular rickettsiosis, Rickettsia akari, R akari, Allodermanyssus sanguineus, A sanguineus,Liponyssoides sanguineus, L sanguineus, Mus musculus, M musculus, spotted-fever group of rickettsiae, papule, maculopapulovesicular exanthema, leukocytosis, leukopenia, lymphadenopathy, chickenpox, boutonneuse fever, hand-foot-and-mouth disease, scrub typhus

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Contributor Information and Disclosures

Author

Julie A Ake, MD, Fellow, Infectious Disease Service, Walter Reed Army Medical Center
Disclosure: Nothing to disclose.

Coauthor(s)

Richard J Scarfone, MD, Associate Professor, Department of Pediatrics, University of Pennsylvania School of Medicine; Attending Physician and Director of Emergency Preparedness, Division of Emergency Medicine, The Children's Hospital of Philadelphia
Richard J Scarfone, MD is a member of the following medical societies: Alpha Omega Alpha and American Academy of Pediatrics
Disclosure: Nothing to disclose.

Timothy J Whitman, DO, Consulting Staff, Department of Infectious Disease, National Naval Medical Center
Disclosure: Nothing to disclose.

Chi Hiong U Go, MD, Assistant Professor, Department of Internal Medicine, Texas Tech University Health Science Center at Odessa
Chi Hiong U Go, MD is a member of the following medical societies: American College of Physicians-American Society of Internal Medicine
Disclosure: Nothing to disclose.

Medical Editor

Fred A Lopez, MD, Vice-Chair, Department of Internal Medicine, Division of Infectious Diseases, Assistant Professor, Louisiana State University School of Medicine
Fred A Lopez, MD is a member of the following medical societies: Alpha Omega Alpha, American College of Physicians-American Society of Internal Medicine, Infectious Diseases Society of America, and Louisiana State Medical Society
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

Charles V Sanders, MD, Edgar Hull Professor and Chairman, Department of Internal Medicine, Professor of Microbiology, Immunology and Parasitology, Louisiana State University School of Medicine at New Orleans; Medical Director, Medicine Hospital Center, Charity Hospital and Medical Center of Louisiana at New Orleans; Consulting Staff, Ochsner Medical Center
Charles V Sanders, MD is a member of the following medical societies: Alliance for the Prudent Use of Antibiotics, Alpha Omega Alpha, American Association for the Advancement of Science, American Association of University Professors, American Clinical and Climatological Association, American College of Physician Executives, American College of Physicians, American Federation for Medical Research, American Foundation for AIDS Research, American Geriatrics Society, American Lung Association, American Medical Association, American Society for Microbiology, American Thoracic Society, American Venereal Disease Association, Association for Professionals in Infection Control and Epidemiology, Association of American Medical Colleges, Association of American Physicians, Association of Professors of Medicine, Infectious Disease Society for Obstetrics and Gynecology, Infectious Diseases Society of America, Louisiana State Medical Society, Orleans Parish Medical Society, Royal Society of Medicine, Sigma Xi, Society of General Internal Medicine, Southeastern Clinical Club, Southern Medical Association, Southern Society for Clinical Investigation, and Southwestern Association of Clinical Microbiology
Disclosure: Nothing to disclose.

CME Editor

Eleftherios Mylonakis, MD, Clinical and Research Fellow, Department of Internal Medicine, Division of Infectious Diseases, Massachusetts General Hospital
Eleftherios Mylonakis, MD is a member of the following medical societies: American Association for the Advancement of Science, American College of Physicians, American Society for Microbiology, and Infectious Diseases Society of America
Disclosure: Nothing to disclose.

Chief Editor

Burke A Cunha, MD, Professor of Medicine, State University of New York School of Medicine at Stony Brook; Chief, Infectious Disease Division, Winthrop-University Hospital
Burke A Cunha, MD is a member of the following medical societies: American College of Chest Physicians, American College of Physicians, and Infectious Diseases Society of America
Disclosure: Nothing to disclose.

 
 
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