Symptoms and Signs of Anthrax

Medical Author: John P. Cunha, DO, FACOEP
Medically Reviewed on 3/11/2019

Doctor's Notes on Anthrax

Anthrax is caused by exposure to the spores of the bacteria Bacillus anthracis that become established in the host body and produce lethal poisons. There are three main ways anthrax can affect humans: through tiny breaks in the skin, inhaled into the lungs, or ingested.

Symptoms of anthrax exposure depend on the way it enters the body. Symptoms of cutaneous (skin) anthrax begin as a small pimple-like sore that enlarges in 24-48 hours to form a "malignant pustule" at the site of the infection. This sore is round with a raised edge, is not painful, and the central area of infection is surrounded by small blisters. A black scab forms at the site of the sore in seven to 10 days and lasts for seven to 14 days before separating. The surrounding area may be swollen and painful. Symptoms of inhalational anthrax begin abruptly, after inhaling large amounts of anthrax spores and may include low-grade fever, sore throat, nonproductive cough, and chest pain. As inhalational anthrax progresses symptoms include high fever, severe shortness of breath, rapid breathing, bluish color to the skin, a great deal of sweating, vomiting blood, and severe chest pain. Inhalational anthrax can often be fatal. Symptoms of intestinal anthrax include nausea, vomiting (may vomit blood), tiredness, no appetite, abdominal pain, bloody diarrhea, and fever. Shock and death may occur two to five days after it begins. Other forms of anthrax exposure may cause additional symptoms.


Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.