What is Nocardiosis?

Nocardiosis is a potentially serious infection caused by bacteria from the Nocardia genus. Most cases primarily affect the respiratory tract, causing chest pain and breathing problems, but the skin and other organs can also become infected. Nocardiosis can be difficult to treat, especially if the infection is not detected in its earliest stages. Long-term use of prescription antibiotics can reduce symptoms and eventually cure the illness in most patients.

Different species of Nocardia are found in soils worldwide, and most people come into regular contact with the bacteria without developing infections. Nocardiosis is most likely to affect people with weakened immune systems, such as the elderly, HIV-positive individuals, and patients who take immunosuppressive drugs for various health reasons. Most cases of nocardiosis result from inhaling the bacteria, but infection can also occur if contaminated dirt gets into an open wound or cut on the skin.

When Nocardia bacteria are inhaled, they attach to the walls of the lungs and respiratory tract. The bacteria initially cause small, asymptomatic lesions to develop. Over time, lesions become larger and create abscesses that can cause breathing difficulties, chest pain, and a wet, bloody cough. Many people experience chills and fevers as their infections worsen. An untreated case of nocardiosis can result in permanent lung scarring and eventual respiratory failure.

Skin infections often lead to large, painful ulcers that are initially isolated to the site of infection. Nocardia bacteria can spread quickly in the skin, however, causing ulceration on other parts of the body. The lymph nodes may swell and fever, night sweats, and headaches are common. Rarely, bacteria can penetrate the brain and cause life-threatening complications.

A doctor who suspects nocardiosis can perform a series of diagnostic tests. In the case of a lung infection, he or she takes imaging scans of the chest to look for damage and extracts a blood sample for laboratory analysis. A sample of skin tissue is collected in the case of a cutaneous infection so that pathologists can check for the presence of Nocardia bacteria. Treatment is initiated immediately after confirming the diagnosis to provide the best chances of recovery.

An antibiotic called sulfadiazine is usually prescribed for all types of nocardiosis. Since the bacteria are notoriously difficult to suppress, patients typically need to take daily doses of sulfadiazine for two to six months or longer. Additional anti-inflammatory or pain-relieving medications may also be prescribed, depending on the severity of a person's symptoms. Surgery is necessary in rare cases where skin, brain, or lung abscesses grow large enough to cause fatal complications.