Last Updated 05/18/2020
Author:Chadi A. Hage, MD, FCCP
- Histoplasmosis is the most common of the 3 major fungus infections in North America.
- Histoplasmosis is usually mild in healthy people.
- People who have poor health can get more severe types of histoplasmosis.
- People who smoke or have emphysema (a type of lung disease) can get worse kinds of histoplasmosis that require long treatment.
Histoplasmosis is an infection caused by the fungus Histoplasma capsulatum (H. capsulatum). It is endemic, which means that it occurs in specific areas in North America. Most histoplasmosis occurs in a large part of the Midwest around the Ohio and Mississippi river valleys. A few cases have been found in the northern plains and southeastern United States. Histoplasmosis is also common in Latin America and Africa.
How Histoplasmosis affects your body
You can get histoplasmosis if you breathe fungus spores (small parts of the fungus) in the air. Fungus spores get into the air when layers of earth are disturbed during, for example:
- Tearing down old buildings;
- Cutting down old trees;
- Large construction projects; and
- Exploring caves in which bats roost.
If you breathe in the fungus spores, you can get a lung infection (called pneumonia). If you’re not healthy, the infection can spread throughout your body.
Most histoplasmosis infections aren’t serious, and many healthy people don’t even know they have one. Infections can be worse if you have a lot of contact with the fungus or if you aren’t otherwise healthy. In these cases, you may experience a failing respiratory (breathing) system and shock. How serious the infection is depends on 3 things:
- How much you were exposed to the fungus;
- How healthy you are; and
- How healthy your lungs are.
Symptoms of Histoplasmosis
Healthy people who get histoplasmosis don’t have many symptoms. If they become sick, they tend to get better quickly on their own. In people who are not healthy, such as people who have HIV/AIDS and those who take medications to suppress their immune system, histoplasmosis can be dangerous.
Three types of histoplasmosis require medication:
- Acute histoplasmosis
- Chronic cavitary histoplasmosis
- Disseminated histoplasmosis
Some people still may have symptoms after the infection has been cured, but they usually do not require more medication.
What are the symptoms of acute Histoplasmosis?
Acute histoplasmosis usually shows up 2 to 4 weeks after you breathe in the spores. It may start earlier if you have breathed in lots of spores. The most common symptoms of acute histoplasmosis are:
- Fever and chills, flu-like illness;
- Muscle pain;
- Loss of appetite;
- Shortness of breath;
- Dry cough; and
- Chest pain.
Most symptoms go away in a few weeks. People who breathe in lots of spores may lose the ability to breath and need to go to the hospital for help to breathe.
What are the symptoms of chronic Histoplasmosis?
People who have emphysema often get a slow-growing form of histoplasmosis. It may look like tuberculosis (TB), but it’s not contagious. The most common symptoms of chronic histoplasmosis are:
- Coughing up thick yellow mucus (sputum);
- Shortness of breath;
- Feeling run-down or tired;
- Mild fever and night sweats; and
- Weight loss.
If chronic histoplasmosis isn’t treated, it can damage the lungs and weaken the body.
What are the symptoms of disseminated Histoplasmosis?
People who are not healthy (for example, they have a poor immune system) can’t control even a mild case of histoplasmosis. The infection can move from the lungs and affect all parts of the body, causing a severe illness called disseminated histoplasmosis. The most common symptoms of disseminated histoplasmosis are:
- Fever and chills, flu-like illness;
- Shortness of breath;
- Drop in blood pressure and shock;
- Cough and chest pain;
- Swollen spleen and liver;
- Stomach or intestinal bleeding;
- Sores in the mouth and lips; and
- Low white and/or red blood cell counts (bone marrow failure).
Disseminated histoplasmosis can be deadly unless it’s caught and treated quickly.
What causes Histoplasmosis?
Certain areas contain H. capsulatum or activities that can cause you to breathe in H. capsulatum:
- Caves (exploring)
- Chicken coops (cleaning, destroying, and use of bird droppings in gardens)
- Bird roost (destroying)
- Prison grounds and school yards (cleaning and routine activities)
- Decayed wood pile (cutting and moving the wood)
- Dead trees (cutting wood and recreation)
- Old buildings (destroying, remodeling, cleaning)
What are the risk factors for Histoplasmosis?
Anyone who lives in the geographic area of the fungus can get a mild infection that heals itself. The fungus typically remains in the body and never causes a problem. If the person becomes weak, the fungus may become active again. The following conditions and events can weaken your body and lead to more serious histoplasmosis:
- Organ transplant
- Drugs that suppress the immune system:
- Tumor necrosis factor (TNF) blockers, such as infliximab
- Corticosteroids, such as prednisone
- Antirejection medications, such as mycophenolate and azathioprine
- Very young or very old age
How is acute Histoplasmosis diagnosed?
To diagnose acute histoplasmosis, health care providers ask patients questions about whether they breathed in the fungus spores. They will also do a physical examination and order tests to check the diagnosis of acute histoplasmosis. These tests include a blood test to see if H. capsulatum has left traces (called antigens) in the blood. The blood test may not show infection (negative) if it’s done too soon after the infection begins. Blood tests may be done again a few weeks later to confirm the infection. If the infection is mild, the trace may not show up in the blood.
How is chronic Histoplasmosis diagnosed?
If a person has emphysema, gets symptoms that are like TB, and breathed in the fungus spores, health care providers may suspect chronic histoplasmosis. A chest X-ray may show lungs filled with fluid. In addition, blood tests for H. capsulatum are usually positive, and mucus specimens typically grow H. capsulatum.
How is disseminated Histoplasmosis diagnosed?
It is important to diagnose disseminated histoplasmosis quickly so that medication can begin and patients can have a better outcome . If a provider suspects disseminated histoplasmosis, he or she may order 2 tests:Blood test for H. capsulatum antigens
Looking at the air passageways by bronchoscopy for infection
Contact your provider if you:
- Live in the Midwestern United States;
- Have done activities that can cause histoplasmosis; or
- Your immune system is weak and you have symptoms of a respiratory tract infection.
How is acute Histoplasmosis treated?
Most people with acute histoplasmosis get better by themselves after a few weeks. If symptoms are bad or last more than 4 weeks, the should be on medication. The best medication—oral itraconazole—is taken for 12 weeks. Patients with serious acute histoplasmosis that leads to breathing failure are given intravenous (IV) amphotericin B for 1 to 2 weeks, and then take oral itraconazole for 12 more weeks.
How is chronic Histoplasmosis treated?
Chronic histoplasmosis is treated with oral itraconazole taken for 12 to 18 months until there are no more signs of the infection.
How is disseminated Histoplasmosis treated?
It can be difficult to treat people who have disseminated histoplasmosis. First, these patients receive IV medication (amphotericin B) for 2 weeks, then they take oral itraconazole for 12 months. They may also need devices (mechanical ventilation) to help them breathe. If they are on medication for other illnesses, those medications may need to be changed so that the histoplasmosis medications can work.
If histoplasmosis is found and treatment started quickly, people usually make a good recovery. If your health care provider suspects that you may have histoplasmosis, you may need to:
- Miss school or work for a few weeks because of symptoms;
- Have a chest X-ray or chest computed tomography (CT) scan and blood test to diagnose histoplasmosis;
- Undergo bronchoscopy, a procedure performed under sedation by lung doctors (called pulmonologists) to inspect the lungs with a small camera and collect samples with a small needle;
- Take medication for a long time; and
- Repeat chest X-rays and blood tests to make sure the infection is gone.
Stay away from things that irritate your lungs. Don’t smoke. If you need to use items such as paint, paint remover, or varnish, wear a mask over your nose and mouth.
Other ways to help prevent acute bronchitis (or lung infection) include:
- Washing your hands often to remove viruses and bacteria; and
- Getting a flu shot every year.
Ask your provider if you should get a pneumonia shot, especially if you’re 60 years of age or older.
For more information about the epidemiology and management of histoplasmosis, please visit the Centers for Disease Control and Prevention (CDC) website at http://www.cdc.gov/fungal/diseases/histoplasmosis.
The American Lung Association recommends that patients and caregivers join its Living with Lung Disease support community to connect with others facing this disease. To talk to a trained lung professional, call the American Lung Association’s Lung Helpline at 1-800-LUNGUSA. They can help answer your questions and connect you with additional support.
Questions to ask your health care provider
Making notes before your visit and taking along a trusted family member or friend can help you through the first appointment with your provider. You can ask your health care provider questions such as the following:
- What caused me to get histoplasmosis? Do I have any other lung disease or immune deficiency that makes it easier for me to get histoplasmosis?
- Could I give this infection to friends and family members? (No.)
- Do I need to get a chest X-ray or chest CT? (Most of the time, yes.)
- Will antifungal therapy (medications) make me feel better? (Most of the time, yes.)
- Can histoplasmosis be treated, and is the therapy effective? (Typically, yes.)
- How long will it take to recover from my infection with histoplasmosis? (Most of the serious symptoms, such as fever and shortness of breath, will get better with a couple of weeks on medication. You may feel tired and have chest pains for several months.)
- Should I be treated with medications (antifungal therapy)? For how long?
- Should I get tested for other diseases, such as emphysema and HIV?