Identifying Cutaneous Anthrax
Cases of cutaneous anthrax have recently been reported and widely publicized. Practitioners, therefore, may see patients with skin lesions who are concerned about the possibility of having contracted cutaneous anthrax. The following will help practitioners identify true cases of cutaneous anthrax. FIGURE
Etiology:Bacillus anthracis, the etiologic agent of anthrax, is a large, Gram-positive, nonmotile, spore-forming bacterial rod. The 3 virulence factors of B anthracis are edema toxin, lethal toxin, and capsular antigen. Approximately 95% of cutaneous anthrax infections occur when the bacterium enters a cut or abrasion on the skin.
Symptoms: Skin infection begins as a raised itchy bump that resembles an insect bite. In 1 to 2 days, it develops into a vesicle and then a painless ulcer, usually 1 to 3 cm in diameter, with a characteristic black necrotic area in the center. Lymph glands in the adjacent area may swell. About 20% of untreated cases of cutaneous anthrax will result in death; however, death is rare with appropriate antimicrobial therapy.
Diagnosis: Cutaneous anthrax is diagnosed by isolating Bacillus anthracis from a culture of a skin lesion or by measuring specific antibodies in the blood.
Treatment: Because it is easily recognized, cutaneous anthrax is usually treated early and cured. Broad-spectrum antibiotics, such as penicillin, tetracyclines, and fluoroquinolones, are effective in treating uncomplicated cases of cutaneous anthrax. A patient who is febrile or has evidence of a systemic infection should be managed with the recommended treatment regimen for inhalation anthrax, as opposed to the less-complicated regimens recommended for treatment of cutaneous anthrax.
Transmission: Direct person-to-person spread of anthrax is rare.
Source: Centers for Disease Control and Prevention. Disease information: anthrax. [Online] 2001; available at: http://www.cdc.gov/ncidod/dbmd/diseaseinfo/anthrax_g.htm. Accessed October 31, 2001.