Cutaneous Anthrax
Anthrax is caused by Bacillus anthracis, a sporulating, gram-negative bacillus. B. anthracis can be part of the normal soil, and poses a risk to grazing animals. Natural infection occurs when humans become accidentally infected through contact with infected animals or their products.
The primary lesion of cutaneous anthrax begins as a painless, pruritic papule that appears 1 to 7 days after inoculation. The papule enlarges, and within 1 to 2 days, small vesicles or a larger, 1- to 2-cm vesicle forms on the papule that is filled with clear or serosanguineous fluid. As the vesicle enlarges, satellite vesicles may form. Fluid within the vesicles may contain numerous, large gram-positive bacilli and a paucity of neutrophils. Within 1 to 2 days, the vesicle ruptures, undergoes necrosis, and enlarges, forming painless ulcer covered by a characteristic black eschar. Surrounding the ulcer and eschar is a characteristic, non-pitting, gelatinous edema that appears out of proportion to the size of the ulcer. Symptoms include low-grade fever and malaise. Regional lymphadenopathy is present early on.
Clinical characteristics highly suggestive of cutaneous anthrax include (1) a painless ulcer covered with black eschar (2) surrounding edema out of proportion to the size of the ulcer; and (3) a paucity of neutrophils in vesicular fluid.
Used with Permission from the Center for Public Health
and Disasters of California
Search PIER® - Decision Support
ACP Members Only. Decision support for over 460 clinical topics.
Quality Improvement Programs: Our Quality Improvement programs strive to bridge the gap between research and practice.
Adult Immunization: Inform, Implement, Immunize: ACP's Immunization Outreach Program
Discount Ending Soon!
Register now for Internal Medicine 2010 in Toronto, Canada and save! Join us at the premier scientific event in internal medicine and the subspecialties. View pricing details.
Your Opinion Counts
Twice a year, ACP participates in a journal readership survey of random internists. If you receive one of these surveys in the mail, please indicate if you read our journals and answer the questions about your reading habits of our journals.
Your voice in these surveys is very important to ACP and enables us to continue to produce the high-quality publications that you expect.
Find out more.