The physical appearance of the skin lesions is characteristic, and Gram's stains and cultures of the ulcer base are frequently positive. A history of exposure to dust from a contaminated animal product can usually be obtained in the prodromal phase of the respiratory illness, when symptoms are mild. In the absence of a thorough history, the disease is initially mistaken for a viral respiratory illness or bronchitis. Patients with gastrointestinal disease have a history of eating undercooked, often spoiled meat. Enzyme-linked immunosorbent assays are available that measure antibody titers against lethal and edema toxin.
Lesions usually become culture negative within hours of the initiation of therapy.
However, treatment should be continued for seven to 10 days. For penicillin-allergic patients, oral tetracycline, 0.5 g every six hours, is effective for cutaneous disease. Erythromycin and chloramphenicol are also satisfactory alternatives. Excision of skin lesions is contraindicated because of the increased risk of precipitating bacteremia. A killed vaccine derived from a component of the exotoxin is available and is recommended for all industrial workers at risk for exposure to contaminated animal products.