Histoplasmosis is an infection caused by the fungus, Histoplasma capsulatum. The lungs are the usual site of the infection.
What is going on in the body?
Histoplasmosis occurs in many areas of the world. The fungus is found in soil that is contaminated with bird or bat droppings. It usually gets into the body when it is inhaled into the lungs. Most of the time, the infection stays in the lungs and causes respiratory problems. If the infection travels to other body organs, it is known as disseminated histoplasmosis.
What are the causes and risks of the infection?
In a geographic area where the fungus is common, up to 80% of the people have been exposed to the fungus. Most people don't develop any symptoms.
The following groups are more likely to develop symptoms of the infection:
- elderly individuals
- individuals with chronic lung disease, such as COPD
- people with immunodeficiency disorders, such as HIV infection
- young children
People with AIDS or cancer are more likely to develop disseminated histoplasmosis.
What can be done to prevent the infection?
People at high risk for histoplasmosis should avoid contact with soil contaminated by bird or bat droppings. These areas include caves, poultry houses, barns, and other enclosed spaces.
How is the infection diagnosed?
Diagnosis of histoplasmosis begins with a medical history and physical exam.
The healthcare professional may order the following tests:
- an antibody titer test
- chest X-ray
- tests of urine, blood, and other tissues to look for the fungus
Long Term Effects
What are the long-term effects of the infection?
Many people with histoplasmosis have only mild symptoms that go away by themselves. Occasionally, the infection can cause severe respiratory insufficiency and even death.
What are the risks to others?
Histoplasmosis is not contagious and cannot be passed from person to person.
What are the treatments for the infection?
Most people with histoplasmosis have mild cases that do not need to be treated. More serious cases can be treated with amphotericin B, ketoconazole (i.e., Nizoral), itraconazole (i.e., Sporanox), or fluconazole (i.e., Diflucan, although this is not FDA approved for histoplasmosis).
What are the side effects of the treatments?
Amphotericin B can cause chills, fever, low blood pressure, and kidney damage. Fluconazole and itraconazole may cause liver disease. Any of the medicines can cause allergic reactions.
What happens after treatment for the infection?
People with HIV infection may need to remain on lifelong therapy to prevent relapse of the histoplasmosis.
How is the infection monitored?
Any new or worsening symptoms should be reported to the healthcare professional. Special blood tests can be used to detect relapse.