Histoplasmosis

What is histoplasmosis?

Histoplasmosis, also called Darling’s disease, is a fungal infection caused by the fungus Histoplasma capsulatum, which is widespread in the Mississippi and Ohio river valleys and the North-eastern region of America. It is also present in some parts of Central and South America, Africa, Asia and Australia.

What are its main signs and symptoms?

Commonly, people experience minimal or no symptoms of histoplasmosis.

Signs and symptoms of histoplasmosis may include:

• Fever
• Chills
• Productive cough
• Headache
• Loss of appetite
• Lymphadenopathy
• Enlargement of liver or spleen
• Subcutaneous nodules
• Suppurative arthritis
• Spots or scars on the chest

What are the main causes?

Histoplasmosis is caused by an infection of the fungus, Histoplasma capsulatum. It is commonly caused by inhaling airborne spores of Histoplasma fungus.

The infection is often transmitted when the spores from bird droppings are airborne during clean-up drives.

Risk factors:

• Farmers or workers who are involved in tree cutting and demolition work are at a higher risk of acquiring the disease, as the spores are also commonly found in the soil.
• People living in the regions of Mississippi and Ohio river valleys and the North-eastern United States are commonly affected by histoplasmosis because of the fungus being widespread in the soil of these areas.
• Infants and people with a weak immune system are also known to be affected with a severe form of this disease.

How is it diagnosed and treated?

Diagnosis of histoplasmosis requires medical and travel history, clinical examination and assessment of symptoms along with laboratory investigations.

Investigations include:

• Blood and urine test to detect histoplasma antigens
• Chest X-ray and CT scans
• Sputum culture
• Lung biopsy

The treatment of histoplasmosis and its duration depend on the severity of the disease.

Mild form of the disease usually resolves on its own without any specific treatment.

In moderate to severe cases, your doctor will prescribe anti-fungal agents which can be taken orally or may be administered intravenously.

1. MedlinePlus Medical Encyclopedia: US National Library of Medicine; Histoplasmosis.
2. American Thoracic Society. [Internet]. United States. 1905; Histoplasmosis.
3. Center for Disease Control and Prevention [internet], Atlanta (GA): US Department of Health and Human Services; Histoplasmosis.
4. Center for Disease Control and Prevention [internet], Atlanta (GA): US Department of Health and Human Services; About Histoplasmosis.
5. Carol A. Kauffman. Histoplasmosis: a Clinical and Laboratory Update. Clin Microbiol Rev. 2007 Jan; 20(1): 115–132. PMID: 17223625