Nocardiosis is a rare infectious condition that begins in the lungs or skin and can spread to the brain and other organs. In some cases it can be fatal. It is caused by a number of different fungus-like bacteria that are found in the soil. Humans can become infected by inhaling contaminated dust or, less commonly, by wounds or cuts becoming contaminated. It cannot be passed from person to person.
Nocardiosis occurs worldwide in people of all ages. However, it occurs more commonly in older adults and in people with weakened immune systems. Men are affected more often than women. There are two main forms of nocardiosis - disseminated and/or pulmonary infection, and cutaneous infection.
Signs and symptoms
Signs and symptoms will vary according to the type of nocardiosis infection. Disseminated and/or pulmonary nocardiosis affects the lungs and often presents with the following symptoms:
- Cough – often producing a thick phlegm
- Chest pain.
Night sweats, fatigue and weakness, lack of appetite and weight loss may also be experienced.
In up to 30% of cases the infection enters the bloodstream and spreads to other organs (most commonly the brain) where it causes abscesses. When the brain is affected symptoms experienced can include:
In cutaneous nocardiosis infection, pus-filled blisters or ulcerations develop on the skin. This form of nocardiosis most commonly develops after a scratch or cut to the skin. In very rare cases is can spread to the lungs, brain and other organs.
The bacteria that cause nocardiosis can be difficult to identify. Diagnosis can be made by analysis of phlegm, pus or skin biopsy specimens and by taking a thorough medical history. It is important that nocardiosis is diagnosed and treated as early as possible. Early treatment, before it has spread to the brain, provides the best chance of recovery.
High doses of antibiotics are the usual treatment for nocardiosis. The bacteria that cause nocardiosis are usually resistant to penicillin so other antibiotics may be prescribed. These include trimethoprim and erythromycin. In cases of minor infection, treatment duration is usually around 6 weeks. However, in cases of severe infection antibiotic treatment may be needed for up to 12 months, and sometimes longer.
Surgery to drain and/or remove abscesses may also be required.
Disseminated and/or pulmonary nocardiosis is a serious condition that is fatal in up to 10% of uncomplicated cases – even when appropriate treatment has been given. The fatality rate can be considerably higher if the infection has spread to the brain. Cutaneous nocardiosis is rarely fatal, however long terms infection can lead to significant scarring.
Centre for Disease Control and Prevention (2013) Nocardiosis. Division of Bacterial and Mycotic Diseases; Centre for Disease Control and Prevention, Atlanta, GA. http://www.cdc.gov/nocardiosis/
New Zealand Dermatological Society Inc. (2013) Nocardiosis. In DermNet NZ. New Zealand Dermatological Society Inc. http://dermnetnz.org/bacterial/nocardiosis.html
Turkington, C. A. (2006) Nocardiosis. The Gale Encyclopedia of Medicine, Third Edition. Jacqueline L. Longe, Editor. Farmington Hills, MI. Thompson Gale.
Last Reviewed – 5 September 2013