What Is Nocardiosis?

Medically Reviewed by Sabrina Felson, MD on May 29, 2023
3 min read

Nocardiosis is a disease caused by bacteria found in soil or standing water. It starts in your lungs or skin, and can cause serious problems if it gets into your bloodstream and infects other parts of your body.

Nocardiosis comes in two forms. You get the pulmonary (lung) version from breathing in the bacteria. The second type is primary cutaneous (skin). That’s when the bacteria gets into an open wound like a scratch.

Between 500 and 1,000 people get it each year in the United States. Men are three times more likely to be infected by it than women -- middle-aged men working outdoors are at the highest risk. You also may have a greater chance of getting it if you have a weak immune system because of a condition like diabetes, HIV, or cancer, or if you’ve had a bone-marrow or organ transplant. If you’ve taken high doses of powerful steroids (drugs that help with inflammation), it also increases your chances.

The signs can be different, depending on which type you have. Pulmonary nocardiosis is the most common, and its symptoms are a lot like ones you might have with pneumonia or tuberculosis:

The most common signs of primary cutaneous nocardiosis are skin abscesses on your hands, chest, or rear end. These are bumps on or below the skin’s surface that are usually filled with a fluid (pus). You also might have a fever.

If not treated, the infection can spread through your bloodstream to your brain or, more rarely, to your kidneys, intestines, or other organs. It can be very serious. Signs that the infection has spread to your brain include:

  • Bad headaches
  • Motor skills problem, like balance or hand-eye coordination
  • Extreme sensitivity to loud sounds or bright lights

If you have any of these symptoms, see your doctor right away.

It can be hard to tell the difference between pulmonary nocardiosis and pneumonia or tuberculosis. And primary cutaneous nocardiosis looks a lot like several other, more common skin infections.

To find out for sure, your doctor probably will take a small sample of tissue or fluid from the area where you’re infected. This might include tissue or mucus from your lungs or tissue from your skin.

If the infection is in your lungs, you might get a chest X-ray -- or a CT scan, which takes X-rays from several angles and puts them together to make a more detailed image.

Nocardiosis usually can be cured with antibiotics, but not all of them will work against the bacteria. Your doctor might need to run some lab tests to see which ones will work best for you. Then you might need to take them for 6 weeks up to a year, depending on how serious your infection is.

In some cases, you might need surgery to remove or drain abscesses in infected areas.