Histoplasmosis
Fungal infection - histoplasmosis; Ohio River Valley fever; Fibrosing mediastinitisHistoplasmosis is an infection that occurs from breathing in the spores of the fungus Histoplasma capsulatum.
Causes
Histoplasmosis occurs throughout the world. In the United States, it is most common in the southeastern, mid-Atlantic, and central states, especially in the Mississippi and Ohio River valleys.
Histoplasma fungus grows as a mold in the soil. You may get sick when you breathe in spores produced by the fungus. Soil that contains bird or bat droppings may have larger amounts of this fungus. The threat is greatest after an old building is torn down, or in caves.
This infection can occur in people with a healthy immune system. But, having a weakened immune system increases the risk of getting or reactivating this disease. Very young or very old people, or those with HIV/AIDS, cancer, or an organ transplant have more severe symptoms.
HIV/AIDS
Human immunodeficiency virus (HIV) is the virus that causes acquired immunodeficiency syndrome (AIDS). When a person becomes infected with HIV, the ...
Read Article Now Book Mark ArticlePeople with long-term (chronic) lung disease (such as emphysema and bronchiectasis) are also at higher risk for a more severe infection.
Bronchiectasis
Bronchiectasis is a disease in which the large airways in the lungs are damaged. This causes the airways to become permanently wider. Bronchiectasis...
Read Article Now Book Mark ArticleSymptoms
Most people have no symptoms, or only have a mild, flu-like illness.
If symptoms do occur, they may include:
- Fever and chills
Chills
Chills refers to feeling cold after being in a cold environment. The word can also refer to an episode of shivering along with paleness and feeling ...
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Cough and chest pain that gets worse when breathing in
Chest pain
Chest pain is discomfort or pain that you feel anywhere along the front of your body between your neck and upper abdomen.
Read Article Now Book Mark Article - Joint pain
- Mouth sores
Mouth sores
There are different types of mouth sores. They can occur anywhere in the mouth including bottom of the mouth, inner cheeks, gums, lips, and tongue....
Read Article Now Book Mark Article - Red skin bumps, most often on the lower legs
The infection may be active for a short period of time, and then the symptoms go away. Sometimes, the lung infection may become chronic. Symptoms include:
- Chest pain and shortness of breath
- Cough, possibly coughing up blood
- Fever and sweating
In a small number of people, especially in those with a weakened immune system, histoplasmosis spreads throughout the body. This is called disseminated histoplasmosis. In response to the infection irritation and swelling (inflammation) occur. Symptoms may include:
- Chest pain from inflammation of the sac-like covering around the heart (pericarditis)
Pericarditis
Pericarditis is a condition in which the sac-like covering around the heart (pericardium) becomes inflamed.
Read Article Now Book Mark Article - Headache and neck stiffness from swelling of the membranes covering of the brain and spinal cord (meningitis)
Meningitis
Meningitis is an infection of the membranes covering the brain and spinal cord. This covering is called the meninges.
Read Article Now Book Mark Article - High fever
Exams and Tests
Histoplasmosis is diagnosed by:
- Biopsy of the lung, skin, liver, or bone marrow
Biopsy
A biopsy is the removal of a small piece of tissue for laboratory examination.
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Urine or blood tests to detect histoplasma proteins or antibodies
Blood
Histoplasma complement fixation is a blood test that checks for infection by a fungus called Histoplasma capsulatum (H capsulatum), which causes the ...
Read Article Now Book Mark Article - Cultures of the blood, urine, or sputum (this test provides the clearest diagnosis of histoplasmosis, but results can take 6 weeks)
To help diagnose this condition, your health care provider may do a:
- Bronchoscopy (test that uses a viewing scope inserted into the lung airway to check for signs of infection)
Bronchoscopy
Bronchoscopy is a test to view the airways and diagnose lung disease. It may also be used during the treatment of some lung conditions.
Read Article Now Book Mark Article - Chest CT scan
Chest CT scan
A chest CT (computed tomography) scan is an imaging method that uses x-rays to create cross-sectional pictures of the chest and upper abdomen....
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- Spinal tap to look for signs of infection in cerebrospinal fluid (CSF)
Spinal tap
Cerebrospinal fluid (CSF) collection is a test to look at the fluid that surrounds the brain and spinal cord. CSF acts as a cushion, protecting the b...
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Treatment
In otherwise healthy people, this infection usually goes away without treatment.
If you are sick for more than 1 month or are having trouble breathing, your provider may prescribe medicine. The main treatment for histoplasmosis is antifungal drugs.
- Antifungals may need to be given through a vein, depending on the form or stage of disease.
- Some of these medicines can have side effects.
- Long-term treatment with antifungal drugs may be needed for up to 1 to 2 years.
Outlook (Prognosis)
The outlook depends on how severe the infection is, and your general health condition. Some people get better without treatment. An active infection will usually go away with antifungal medicine. But, the infection may leave scarring inside the lung.
The death rate is higher for people with untreated disseminated histoplasmosis who have a weakened immune system.
Possible Complications
Scarring in the chest cavity may put pressure on the:
- Major blood vessels carrying blood to and from the heart
- Heart
- Esophagus (food pipe)
- Lymph nodes
Enlarged lymph nodes in the chest may press on body parts such as the esophagus and blood vessels of the lungs.
When to Contact a Medical Professional
Contact your provider if you live in an area where histoplasmosis is common and you develop:
- Flu-like symptoms
- Chest pain
- Cough
- Shortness of breath
While there are many other illnesses that have similar symptoms, you may need to be tested for histoplasmosis.
Prevention
Histoplasmosis may be prevented by reducing exposure to dust in chicken coops, bat caves, and other high-risk locations. Wear masks and other protective equipment if you work in or go into these environments.
References
Deepe GS. Histoplasma capsulatum (histoplasmosis). In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 263.
Kauffman CA, Galgiani JN, Thompson GR. Endemic mycoses. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 316.
Lungs - illustration
The major features of the lungs include the bronchi, the bronchioles and the alveoli. The alveoli are the microscopic blood vessel-lined sacks in which oxygen and carbon dioxide gas are exchanged.
Lungs
illustration
Acute histoplasmosis - illustration
Histoplasmosis is a fungal infection caused by inhaling dust from spore-infected bird droppings. The acute form is treated with antifungal medication.
Acute histoplasmosis
illustration
Disseminated histoplasmosis - illustration
Histoplasmosis is a fungal infection caused by inhaling dust from spore-infected bird droppings. In the disseminated form, infection spreads throughout the body from the lungs. The death rate is fairly high for people with untreated widespread (disseminated) histoplasmosis, but is reduced significantly with treatment.
Disseminated histoplasmosis
illustration
Histoplasmosis, disseminated in HIV patient - illustration
This is a skin lesion resulting from disseminated histoplasmosis. Histoplasmosis occurs most frequently as a lung infection, however it can infect the skin or become distributed (disseminated) to internal organs.
Histoplasmosis, disseminated in HIV patient
illustration
Fungus - illustration
Fungal infections are caused by microscopic organisms (fungi) that can live on the skin. They can live on the dead tissues of the hair, nails, and outer skin layers.
Fungus
illustration
Lungs - illustration
The major features of the lungs include the bronchi, the bronchioles and the alveoli. The alveoli are the microscopic blood vessel-lined sacks in which oxygen and carbon dioxide gas are exchanged.
Lungs
illustration
Acute histoplasmosis - illustration
Histoplasmosis is a fungal infection caused by inhaling dust from spore-infected bird droppings. The acute form is treated with antifungal medication.
Acute histoplasmosis
illustration
Disseminated histoplasmosis - illustration
Histoplasmosis is a fungal infection caused by inhaling dust from spore-infected bird droppings. In the disseminated form, infection spreads throughout the body from the lungs. The death rate is fairly high for people with untreated widespread (disseminated) histoplasmosis, but is reduced significantly with treatment.
Disseminated histoplasmosis
illustration
Histoplasmosis, disseminated in HIV patient - illustration
This is a skin lesion resulting from disseminated histoplasmosis. Histoplasmosis occurs most frequently as a lung infection, however it can infect the skin or become distributed (disseminated) to internal organs.
Histoplasmosis, disseminated in HIV patient
illustration
Fungus - illustration
Fungal infections are caused by microscopic organisms (fungi) that can live on the skin. They can live on the dead tissues of the hair, nails, and outer skin layers.
Fungus
illustration
Review Date: 12/4/2022
Reviewed By: Jatin M. Vyas, MD, PhD, Associate Professor in Medicine, Harvard Medical School; Associate in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.