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Histoplasmosis

Fungal infection - histoplasmosis; Ohio River Valley fever; Fibrosing mediastinitis

Histoplasmosis is an infection that occurs from breathing in the spores of the fungus Histoplasma capsulatum.

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Lungs
Acute histoplasmosis
Disseminated histoplasmosis
Histoplasmosis, disseminated in HIV patient
Fungus

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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.

People with long-term (chronic) lung disease (such as emphysema and bronchiectasis) are also at higher risk for a more severe infection.

Symptoms

Most people have no symptoms, or only have a mild, flu-like illness.

If symptoms do occur, they may include:

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:

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:

Exams and Tests

Histoplasmosis is diagnosed by:

To help diagnose this condition, your health care provider may do a:

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.

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:

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

Call your provider if you live in an area where histoplasmosis is common and you develop:

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.

Related Information

Bronchiectasis
HIV/AIDS
Pericarditis
Mediastinitis
Meningitis

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.

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Review Date: 12/24/2020  

Reviewed By: Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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