What is histoplasmosis? Does it affect any parts of your body other than the lungs?

Helen

Histoplasmosis is a complex infection caused by a fungus called Histoplasma capsulatum. Histoplasmosis occurs worldwide. In the United States, most cases occur in the central states, especially along the Mississippi and Ohio river basins.

The infection occurs when a person inhales air contaminated with the fungus. Most people never develop symptoms, because the body's disease-fighting immune system can contain the infection. In others, the infection causes flu-like symptoms, including cough, muscle aches and fatigue. Rarely, an infected person develops such complications as joint abnormalities, inflammation of the outer covering of the of the heart (pericarditis), or pneumonia, which can be severe. In most cases, the disease resolves in about two weeks. Pericarditis, when it occurs, can linger, though all signs of it are usually gone by six weeks.

In most cases, the infection never causes symptoms again However, some fungi usually persist in the body in an inactive state. These organisms can reactivate later, causing chronic pneumonia or, rarely, widespread disease. Middle-aged male smokers are at highest risk for developing chronic pneumonia. In these patients, the disease is indistinguishable from tuberculosis, with prolonged cough, fever, fatigue and weight loss.

The rare complication of widespread disease, called disseminated histoplasmosis, typically occurs soon after the initial illness. The infection spreads to involve many different organs, including the heart, liver, spleen, skin and mucous membranes in the mouth. It can even affect the brain, causing tumors within it or inflammation of its covering membrane.

In some patients, disseminated histoplasmosis is a slowly progressing, chronic illness. In others, it is a severe, rapidly fatal disease. Previously healthy people can develop the slowly progressive form, but people with AIDS and other immune disorders are more likely to get it, and they are also at highest risk of the rapidly fatal type.

Fortunately, such severe disease is quite uncommon. There are several good therapies for histoplasmosis, and all but the most serious forms usually have a good outcome if treated properly.