Understanding Nocardiosis: Causes, Symptoms, Diagnosis, and Treatment

Benjamin Seth Martinez | MD

Medically reviewed by Benjamin Seth Martinez | MD, Statpearls - Director of Clinical Content on January 31st, 2024.

Key Takeaways

  • Caused by Nocardia bacteria found in soil, dust, and decaying organic matter—infection occurs through inhalation of airborne particles or contamination of open wounds during outdoor activities.
  • Pulmonary form presents with fever, night sweats, productive cough with thick sputum, and weight loss over weeks to months; cutaneous lesions appear as painful, pus-filled nodules that may ulcerate.
  • Immunocompromised patients face 80% higher risk, including those on corticosteroids >10mg daily, HIV patients with CD4 counts <200, and solid organ transplant recipients within the first year.
  • Diagnosis requires specialized staining (modified acid-fast) and culture of sputum, tissue, or abscess fluid—standard bacterial cultures often miss this slow-growing organism that takes 2-8 weeks to identify.
  • Treatment involves trimethoprim-sulfamethoxazole as first-line therapy for 6-12 months, with alternatives like linezolid or amikacin for severe cases; brain involvement extends treatment to 12-18 months minimum.

Nocardiosis is a rare bacterial infection that can affect your lungs or skin. It is caused by bacteria found in soil or standing water. If left untreated, the infection can spread to other parts of your body, leading to serious complications. In this article, we'll discuss the causes, symptoms, diagnosis, and treatment of nocardiosis.

What Causes Nocardiosis?

Nocardiosis is caused by bacteria that are commonly found in soil or standing water. There are two main types of nocardiosis:

  1. Pulmonary nocardiosis: This type occurs when you breathe in the bacteria, affecting your lungs.

  2. Primary cutaneous nocardiosis: This type occurs when the bacteria enter your body through an open wound, such as a scratch or cut on your skin.

Certain factors can increase your risk of developing nocardiosis, including:

  • Having a weakened immune system due to conditions like diabetes, HIV, or cancer

  • Having undergone a bone-marrow or organ transplant

  • Taking high doses of powerful steroids, which can weaken your immune system

  • Being a middle-aged man who works outdoors

Symptoms of Nocardiosis

The symptoms of nocardiosis can vary depending on the type of infection you have. Pulmonary nocardiosis often presents symptoms similar to pneumonia or tuberculosis, such as:

  • Chest pain

  • Coughing

  • Sweating

  • Chills

  • Feeling weak

  • Lack of appetite

  • Unexplained weight loss

  • Shortness of breath or difficulty breathing

Primary cutaneous nocardiosis typically causes skin abscesses on the hands, chest, or buttocks. These abscesses are usually filled with pus and may be accompanied by a fever.

Understanding Nocardiosis: Causes, Symptoms, Diagnosis, and Treatment

If the infection spreads through your bloodstream to other parts of your body, such as your brain, you may experience additional symptoms like severe headaches, problems with motor skills, or extreme sensitivity to loud sounds or bright lights.

Diagnosing Nocardiosis

Diagnosing nocardiosis can be challenging because its symptoms are similar to other, more common conditions. To confirm the diagnosis, your doctor will likely take a sample of tissue or fluid from the affected area, such as your lungs or skin. They may also order imaging tests, such as a chest X-ray or CT scan, to visualize the extent of the infection in your lungs.

Treating Nocardiosis

Nocardiosis is usually treated with antibiotics. However, not all antibiotics are effective against the bacteria that cause this infection. Your doctor may need to perform lab tests to determine which antibiotics will work best for you. Treatment can last anywhere from 6 weeks to a year, depending on the severity of your infection.

In some cases, surgery may be necessary to remove or drain abscesses in the infected areas. It's essential to follow your doctor's instructions and complete the entire course of antibiotics to ensure the infection is fully treated and to prevent it from recurring.

When to Seek Medical Attention

If you experience any symptoms of nocardiosis, especially if you have a weakened immune system or have recently had an open wound, it's crucial to see your doctor right away. Prompt diagnosis and treatment can help prevent the infection from spreading and causing more serious complications.

For more information on nocardiosis, visit the following reputable sources:

The Bottom Line

This opportunistic infection requires aggressive, prolonged antibiotic treatment to prevent life-threatening dissemination to the brain and other organs. Immunocompromised individuals with persistent respiratory symptoms or unusual skin lesions need immediate medical evaluation. If you're experiencing unexplained cough, fever, or skin abscesses that aren't responding to standard treatment, Doctronic can help connect you with appropriate diagnostic testing.

Related Articles

Does Mounjaro Affect Fertility?

Understanding Mounjaro and Its UsesMounjaro is a prescription medication commonly prescribed for managing type 2 diabetes. It belongs to a class of drugs that help regulate [...]

Read More