Anthrax - skin

Definition

Cutaneous anthrax

Alternative Names

Causes

Anthrax is caused by the bacteria Bacillus anthracis. While anthrax commonly affects hoofed animals such as sheep and goats, humans may get sick from anthrax, too. The most common type of anthrax infection is cutaneous anthrax, an infection of the skin.

Historically, the main risk factor for getting cutaneous anthrax is contact with animal hides or hair, bone products, and wool, as well as contact with infected animals. Therefore, those most at risk for anthrax include farm workers, veterinarians, and tannery and wool workers.

Cutaneous anthrax occurs after the bacteria touches a cut or scrape on the skin.

Anthrax is a potential agent for use as a biological weapon or for bioterrorism. In 2001, bioterrorist activities involving the United States Postal Service infected 22 people with anthrax;. Seven survivors had confirmed cutaneous anthrax disease. Most bioterrorism experts have concluded that it is technologically difficult to use anthrax effectively as a weapon on a large scale.

Symptoms

About 2 weeks after infection, an itchy sore develops, similar to an insect bite. This sore may blister and form a black ulcer, which is usually painless. It is usually surrounded by significant swelling. A scab often develops, and then dries and falls off within 2 weeks.

Some patients also have painful lymph nodes, fever, headache, and a general ill-feeling.

Exams and Tests

A culture of the skin lesions should be done to identify the bacteria that causes anthrax.

Treatment

Cutaneous anthrax is treated with antibiotics, including penicillin, doxycycline, and ciprofloxacin. Ciprofloxacin has been the antibiotic of choice during a suspected anthrax outbreak.

Because anthrax spores may take up to 60 days to grow, the length of treatment is usually 60 days.

Outlook (Prognosis)

The outlook is excellent when treated. Death is extremely rare when antibiotics are promptly given.

Possible Complications

In some cases, the infection can spread through the bloodstream, leading to shock and death.

When to Contact a Medical Professional

Call your health care provider if you know you have been exposed to anthrax, or if you develop a skin lesion as described above.

Prevention

For individuals who have been truly exposed to anthrax (but have no signs and symptoms of the disease), preventive antibiotics such as ciprofloxacin, penicillin, or doxycycline may be offered, depending on the particular strain of anthrax.

Cutaneous anthrax is not known to spread from person to person. Household contacts of individuals with cutaneous anthrax do not need antibiotics unless they have also been exposed to the same source of anthrax.

An anthrax vaccine is available to selected military personnel, but not to the general public.

Reissman DB, Whitney EA, Taylor TH Jr, et al. One-Year Health Assessment of Adult Survivors of Bacillus anthracis Infection.  JAMA. 2004;291:1994-1998.

Inglesby TV, O'Toole T, Henderson DA, et al. Anthrax as a Biological Weapon, 2002. JAMA. 2002;287:2236-2252.