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Last updated Dec. 10, 2018

Approved by: Maulik P. Purohit MD MPH

Nocardiosis is a rare, acute and chronic infection which affects the lungs, brain, and skin. It is caused by a bacterium belonging the genus Nocardia, which is found aplenty in the soil.

What are the other Names for this Condition? (Also known as/Synonyms)

  • Cerebral Nocardiosis
  • Lung Nocardiosis
  • Nocardia Infection

What is Nocardiosis? (Definition/Background Information)

  • Nocardiosis is a rare, acute and chronic infection which affects the lungs, brain, and skin. It is caused by a bacterium belonging the genus Nocardia, which is found aplenty in the soil
  • The disease spreads by inhaling contaminated dust or when soil containing the bacteria enters the skin through open wounds
  • Depending on the area infected Nocardiosis is of 3 types, namely:
    • Pulmonary Nocardiosis that infect the lungs
    • Cerebral Nocardiosis that infect the brain
    • Primary Cutaneous Nocardiosis that infect the skin
  • Although Nocardiosis can infect any individual, those with a weakened immune system, particularly men, are reported to be more susceptible to the disease
  • The risk factors for developing the infection include poor immunity, individuals with chronic lung disease, and some therapies for cancer and other diseases
  • Depending on the type of disease, the symptoms vary and can include:
    • Pulmonary Nocardiosis: Weight loss, pneumonia, and chest pain
    • Cerebral Nocardiosis: Headaches, seizures, and meningitis
    • Cutaneous Nocardiosis: Ulcer formation and the spread of infection along the lymph nodes
  • A diagnosis of Nocardia Infection is generally undertaken through biopsies of the infected tissue samples (from the skin, lungs, or even brain)
  • Depending on the site of infection, its extent and severity, complications, such as severe shortness of breath, scarring, disfigurement, loss of neurological functions, and many others, could ensue
  • The treatment options for Nocardiosis involve long-term antibiotic therapy. The skin nodules may be drained or removed surgically
  • However, the prognosis, which can be good or poor, depends upon several factors, most importantly the health status of the individual and the infection type

Who gets Nocardiosis? (Age and Sex Distribution)

  • Any individual is susceptible to developing Nocardiosis irrespective of age, gender, race, or ethnicity
  • However, it is most common in immunocompromised individuals, especially men

What are the Risk Factors for Nocardiosis? (Predisposing Factors)

The risk factors associated with Nocardiosis include:

  • Individuals with weak immunity
  • Those with chronic lung disease
  • Those undergoing long-term steroidal therapy for the following health conditions:
    • Cancer
    • Organ transplant
    • Bone marrow transplant
    • HIV infections or AIDS

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Nocardiosis? (Etiology)

  • Nocardiosis is a rare, infectious condition that develops due to bacterial infection by pathogenic microorganisms in the soil (aerobic actinomycetes) of the genus Nocardia asteroids complex (which cause over half the cases)
  • The N. asteroids complex consist of the following types:
    • N. abscessus
    • N. cyriacigeorgica
    • N. farcinica
    • N. nova
  • Other disease causing Nocardia species include the following:
    • N. transalensis complex
    • N. brasiliensis
    • N. pseudobrasiliensis
  • The disease spreads by inhaling contaminated dust or when soil containing the bacteria enters the skin through open wounds and can infect the lungs, brain, or skin

What are the Signs and Symptoms of Nocardiosis?

The signs and symptoms of Nocardiosis are based upon the type of infection and the region they infect.

  • Signs and symptoms of Pulmonary Nocardiosis include:
    • Weight loss
    • Chest pain when breathing
    • Night sweats
    • Fevers
    • Blood in sputum
    • Progressive form of pneumonia
  • Signs and symptoms of Cerebral Nocardiosis include:
    • Fever
    • Headache
    • Seizures
    • Lethargy
    • Confusion
    • Sudden onset of neurological deficit
    • Cerebral abscess
    • Meningitis
  • Signs and symptoms of Skin or Cutaneous Nocardiosis:
    • Development of draining tracts
    • Ulcers
    • Skin nodules
    • Infection spreading along the lymph nodes

How is Nocardiosis Diagnosed?

The diagnosis of Nocardiosis may involve the following:

  • Complete physical examination with comprehensive medical history evaluation
  • Sputum culture
  • Tissue from the suspected site of infection for culture
  • Tissue biopsy, such as of the brain, bronchus, lung, and skin

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Nocardiosis?

The potential complications that could arise as a result of Nocardiosis are:

  • Lung infection leading to chronic shortness of breath and difficulty in breathing
  • Skin Infection causing damaged skin or disfigurement (including cosmetic issues)
  • Brain abscesses can lead to nerve damage and subsequent loss of neurological function/s.

How is Nocardiosis Treated?

The treatment of Nocardiosis may involve:

  • Long-term antibiotic therapy with sulphonamides for 6 months to 1 year (depending upon the clinical assessment)
  • Chronic suppressive therapy consisting of long-term low dose antibiotic therapy
  • Patients who develop abscesses could be treated through surgery to completely drain the abscesses

How can Nocardiosis be Prevented?

A few preventive methods for Nocardiosis include:

  • Immunocompromised individuals must avoid contact with soil and plants
  • Use of trimethoprim or sulfamethoxazole prophylaxis in the first 6 months after organ transplantation
  • Less than normal count of CD4 T in HIV patients (to some extent, it is reported to prevent Nocardiosis)

There are no vaccinations available at present to prevent Nocardiosis.

What is the Prognosis of Nocardiosis? (Outcomes/Resolutions)

  • The prognosis of Nocardiosis is dictated by the robustness of one’s immune system, the site of infection, its extent, and severity
  • Nocardiosis can be a fatal infection, if more than one site is simultaneously infected

Additional and Relevant Useful Information for Nocardiosis:

The following DoveMed website link is a useful resource for additional information:


What are some Useful Resources for Additional Information?

References and Information Sources used for the Article:

Helpful Peer-Reviewed Medical Articles:

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: Nov. 6, 2015
Last updated: Dec. 10, 2018