Anthrax: Possible Skin Exposure, No Symptoms

Anthrax is an infectious disease caused by anthrax bacteria. The bacteria are spread in the form of spores. A spore is a protective covering on the bacteria, like the shell of a seed. The spore keeps the bacteria alive for long periods of time, waiting for the right condition to grow.

Anthrax can cause an infection in the skin, stomach and intestines, or lungs. People can become infected with anthrax by getting the spores in their bodies. This usually happens by handling infected animals or animal products. Anthrax is uncommon and is generally only seen in underdeveloped countries. It's very rare in North America. Most cases have occurred in people who handle imported animal hides, in people who inject heroin, or in people exposed in a bioterrorism attack.

Skin anthrax occurs after the spores come in contact with an opening in the skin (such as a crack, cut or scrape).

  • Not everyone exposed will get sick.

  • If the infection occurs after exposure, symptoms usually start within 1 to 7 days.

  • The disease starts as a small red bump (like an insect bite) that turns into a blister.

  • The blister breaks in 1 to 2 days. Then a painless black sore forms. This sore dries up in 1 to 2 weeks.


Your provider will tell you what symptoms to watch for. Skin anthrax symptoms start as bumps or blisters, but then get worse. Symptoms can include:

  • A group of small blisters or bumps that may itch

  • A painless skin sore (ulcer) with a black center that appears after the small blisters or bumps

  • Often, a sore on the face, neck, arms, or hands

  • Swelling around the sore

Anthrax infection can only occur after skin is exposed directly to anthrax spores. Skin anthrax can be transmitted to others, but this is very rare. Whether you are treated with antibiotics will depend on the threat of exposure and the time since that exposure.

Home care

  • Don't panic. The illness can be cured if correct treatment is started early after a confirmed exposure.

  • If antibiotics were prescribed, take them exactly as directed.

  • Wash your hands after using the bathroom and before eating and drinking.

Follow-up care

Follow up with your healthcare provider, or as advised.

If a lab test on a sample of cells (culture) was done, you will be notified if the treatment needs to be changed. You can call as directed for the results.

If X-rays or a CT scan were done, they will be reviewed by a specialist. You will be notified of the results, especially if they affect treatment.

Call 911

Call 911 if any of these occur, especially if you have been handling an imported animal hide or have been injecting heroin:

  • A painless bump appears on the skin, especially if it is surrounded by a large area of swelling

  • A black center develops in this bump, especially if swollen lymph nodes in the arm pit, neck, or groin develop

  • Symptoms such as fever, weakness, or headache develop along with the skin findings

When to seek medical advice

Call your healthcare provider or get medical attention right away if any of these occur on the skin within 3 weeks after the possible exposure:

  • Red bump (like an insect bite) or blister

  • Black scab or ulcer on the skin

  • Fever of 100.4ºF (38ºC) or higher, or as directed by your healthcare provider

  • Weakness or dizziness

For the latest information, see the CDC website:, or contact your state public health department.

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