Fungus Among Us: What Patients and Parents Need to Know About Histoplasmosis

What Is Histoplasmosis?

Histoplasmosis is an infection caused by the fungus, Histoplasma capsulatum, which is found as spores in soil, bird and bat droppings and some decaying materials. It is the most common fungal infection in North America. 

Certain geographic areas seem to have more Histoplasma species in the soil. The Ohio and the Mississippi River valley are considered highest-risk areas.

The infection occurs when the fungus is released, circulates in the air and fungal spores are inhaled by an individual.

What Are the Symptoms of Histoplasmosis?

Someone can develop various symptoms within days to weeks after inhaling the fungal spores, including any of the following:

Patients with histoplasmosis infection can develop minimal or mild symptoms, pneumonia, and more severe (also known as disseminated) disease, where the infection affects multiple organs (for example, lungs, bone marrow, liver, spleen, heart, brain). The severity of the infection and symptoms depends on the amount of fungal exposure and the person’s underlying immune system.

Who Is at Risk?

Young infants and individuals with compromised immune systems, including patients who are receiving chemotherapy, have had solid organ or bone marrow transplants, and conditions that affect the immune system are at higher risk of infection, severe disease and complications.

Some children may have a higher risk of getting histoplasmosis and having more severe disease than others.

• Patients who are taking certain medications for cancer, auto-immune diseases, gastrointestinal disorders or dermatologic conditions
• Individuals with chronic pulmonary disease

Individuals who disturb soil and send the fungal spores into the air are also at higher risk. This can be caused by many things, including the following:

• Landscaping – including gardening, fertilizing and mulching
• Exploring caves
• Working or playing around chicken coops, pigeon or other bird roosts
• Exposure to barns, hay lots or animal feed
• Construction, remodeling or cleaning out old buildings
• Being around wood piles, cutting or chopping wood or using natural wood in bonfires
• Exposure to bats

If Someone Is at Risk, What Can They Do to Prevent Infection?

If your child is at risk of getting histoplasmosis, have them avoid the activities listed above. If these exposures are unavoidable, use of a mask may reduce the chances of getting an infection. Masks do not completely eliminate the risk.

How Is It Diagnosed?

A chest x-ray, computed tomography (CT) scan of the lungs or abdomen or heart imaging (CT or echocardiogram) may suggest histoplasmosis, but your child’s doctor may need to run a series of tests to confirm the diagnosis. These tests can range from blood, sputum or urine tests, to biopsies of the liver, lungs, bone marrow or lymph nodes.

How Is It Treated?

When infection is suspected or confirmed, treatment with an antifungal medication is usually needed in young children and immunocompromised individuals. The type of antifungal will depend on the extent and severity of the infection. Depending on the severity of the infection, this will either be an oral pill or an intravenous (IV) medication and treatment can last many months.

If your child develops symptoms that could be histoplasmosis, contact their health care provider as soon as possible.

The Infectious Disease Host Defense Team at Nationwide Children's Hospital is available to help with the diagnosis and management of histoplasmosis infections in immunocompromised children, teenagers, and young adults. Click here to learn more.