7 September 2007
Cutaneous Anthrax: Key References for Clinicians
This week two persons in Danbury, Connecticut (USA) were diagnosed with cutaneous anthrax. The reported source of the infection is imported animal hides being used to make African drums. Today’s New York Times also reported that “six samples collected from a three-story house and a barn in the backyard tested positive for anthrax… (Page A27, Sept 7, by Thomas Kaplan)”
According to the Connecticut Post (ConnPost.com) article September 5th by Robert Miller “staff from Danbury Hospital and the state Department of Public Health emphasized the cases posed no health risk whatsoever to the general public”.
This event can reinforce the importance for clinicians of having useful references readily available with regard to cutaneous anthrax, for example:
---The American College of Physicians (ACP) has posted on their website a PowerPoint presentation with 60 slides titled “Cutaneous Anthrax and its Mimics”. Most of the 20 diseases in the differential diagnosis of cutaneous anthrax also have photos provided. Discussion of all 20 diseases ends with a final slide that helps differentiate the disease from cutaneous anthrax. For example, the bite of the brown recluse spider (Loxosceles reclusa) causes a painful lesion, whereas the lesion of cutanous anthrax is PAINLESS. Also of note, the brown recluse spider bite occurs mainly in the Midwest and Southeast of the US and not in the northeast (e.g., Connecticut). These slides by the ACP and American Society of Internal Medicine are posted at: www.acponline.org/bioterro/#pflu
---The American Society of Dermatology (AAD) posted on their website in November 2001 a detailed “Cutaneous Anthrax Management Algorithm”. This document includes clinical pearls describing the typical appearance and progression of cutaneous anthrax. For example, they note that “pustules are rarely present in anthrax lesions”. Also, although the skin lesion is usually PAINLESS the associated regional lymphadenopathy is usually “tender”. This document also provides specific detailed advice on how best to obtain swab exudates and punch biopsies from the lesion(s), including the type of swab to use, and where exactly to biopsy. This algorithm is posted at: www.aad.org/professionals/educationcme/bioterrorism/CutaneousAnthrax.htm
--- The CDC anthrax webpage (at: www.bt.cdc.gov/agent/anthrax) has a specific section on the diagnosis and management of cutaneous anthrax, as well as images of cutaneous anthrax (at: www.bt.cdc.gov/agent/anthrax/anthrax-images/cutaneous.asp). Additional images, cutaneous and microscopic, are also posted on the CDC’s “Public Health Images Library (PHIL), with the largest number of skin photos on page 5 of 8.
---The Infectious Diseases Society of America (IDSA) website contains comprehensive information on all forms of anthrax (at: www.cidrap.umn.edu/idsa/bt/anthrax/biofacts/anthraxfactsheet.html)
This document includes images of cutaneous anthrax, diagnostic steps, therapy and literature references.
---Additional images of cutaneous anthrax can be found on the homepage of this website (www.BePast.org), as well as on the website of the E-Medicine chapter on dermatologic aspects of anthrax (at: www.emedicine.com/derm/topic913.htm).
Without appropriate antibiotics the case-fatality rate has been approximately 20%. Increased risk of death is linked with airway compression due to a cutaneous lesion on the neck (with characteristic extensive edema), or with the development of bacteremia, especially if complicated by meningitis.
A discussion of all aspects of clinical anthrax is also provided by this author in the most recent (6th) edition (2005) of the textbook “Principles and Practice of Infectious Diseases” edited by Mandell, Bennett, and Dolin (pages 2485-2491 and 3618-3624)
Daniel R. Lucey, MD, MPH
Director, Center for Biologic Counterterrorism and Emerging Diseases
EROne Institutes, Department of Emergency Medicine
Washington Hospital Center
Adjunct Professor of Microbiology and Immunology
Georgetown University Medical Center, Washington, DC
Website for this posting: www.BePast.org