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Clinical manifestations and diagnosis of anthrax

Kenneth H Wilson, MD
Section Editor
Daniel J Sexton, MD
Deputy Editor
Anna R Thorner, MD


Anthrax, caused by Bacillus anthracis, is an uncommon illness in the United States. From 1980 through 2000, only seven cases of anthrax were reported to the Centers for Disease Control and Prevention [1]. In 2001, 22 confirmed or suspected cases of bioterrorism-related anthrax occurred in the United States, when B. anthracis spores in powder-containing envelopes were sent through the mail [2-4]. Subsequent sporadic cases have occurred rarely in the United States, such as in individuals exposed to contaminated animal hides while making traditional drums. (See "Microbiology, pathogenesis, and epidemiology of anthrax".)

The clinical manifestations and diagnosis of anthrax will be reviewed here. The pathogenesis, epidemiology, treatment, and prevention of anthrax are discussed separately. (See "Microbiology, pathogenesis, and epidemiology of anthrax" and "Treatment of anthrax" and "Prevention of anthrax".)


There are three major anthrax syndromes: cutaneous, inhalation, and gastrointestinal tract anthrax [5-7].

Cutaneous — Cutaneous anthrax is the most common form of the disease. Naturally occurring cases of cutaneous anthrax develop after spores of B. anthracis are introduced subcutaneously, often as a result of contact with infected animals or animal products. Cuts or abrasions increase susceptibility to cutaneous infection [8-10]. Spores vegetate and multiply, and the antiphagocytic capsule facilitates local spread. (See "Microbiology, pathogenesis, and epidemiology of anthrax".)

The incubation period is usually 5 to 7 days with a range of 1 to 12 days [11,12]. However, during an anthrax outbreak in Sverdlovsk, Union of Soviet Socialist Republics, cutaneous cases developed up to 13 days following the aerosol release of spores [13]; an outbreak in Algeria was reported with a median incubation period of 19 days [14].

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Literature review current through: Nov 2017. | This topic last updated: Aug 18, 2017.
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