Growing up around a farm, and disturbing contaminated soil while digging are two common reasons for developing Histoplasmosis.

What are the symptoms of Histoplasmosis?

Histoplasmosis is often so mild that it produces no apparent symptoms. Any symptoms that might occur are often similar to those from a common cold. In fact, if you had Histoplasmosis symptoms, you might dismiss them as those from a cold or flu, since the body's immune system normally overcomes the infection in a few days without treatment.

However, Histoplasmosis, even mild cases, can later cause respiratory disorders and a serious eye disease called Presumed Ocular Histoplasmosis Syndrome (POHS).


What is Presumed Ocular Histoplasmosis Syndrome (POHS)?

If Histoplasmosis affects the eye, it is referred to as Presumed Ocular Histoplasmosis syndrome (POHS), or "histo" for short. Histo usually has no symptoms in its early stages; the initial histo infection usually subsides without the need for treatment. This is true for other histo infections; in fact, often the only evidence that the inflammation ever occurred are tiny scars called "histo spots," which remain at the infection sites.

Retina of patient with Histoplasmosis. Note the "histo spots" scattered throughout.

Histo spots do not generally affect vision, but for reasons that are still not well understood, they can result in complications years--sometimes even decades--after the original eye infection. Histo spots have been associated with the growth of the abnormal blood vessels underneath the retina.

In later stages, POHS symptoms may appear if the abnormal blood vessels cause changes in vision. For example, straight lines may appear crooked or wavy, or a blind spot may appear in the field of vision. Because these symptoms indicate that POHS has already progressed enough to affect vision, anyone who has been exposed to Histoplasmosis and perceives even slight changes in vision should consult one of our doctors.

Who is at risk for POHS?

Although only a tiny fraction of the people infected with the histo fungus ever develops POHS, any person who has had Histoplasmosis should be alert for any changes in vision similar to those described above. Studies have shown the POHS patients usually test positive for previous exposure to Histoplasmosis.

In the United States, the highest incidence of Histoplasmosis occurs in a region often referred to as the "Histo Belt," where up to 90 percent of the adult population has been infected by Histoplasmosis. This region includes all of Arkansas, Kentucky, Missouri, Tennessee, and West Virginia as well as large portions of Alabama, Illinois, Indiana, Iowa, Kansas, Louisiana, Maryland, Mississippi, Nebraska, Ohio, Oklahoma, Texas, and Virginia. Since most cases of Histoplasmosis are undiagnosed, anyone who has ever lived in an area known to have a high rate of Histoplasmosis should have their eyes examined for histo spots.

How is POHS diagnosed?

Our doctors will routinely diagnose POHS with a thorough dilated eye examination revealing two signs:

1. The presence of histo spots, which indicate previous exposure to the histo fungus spores.
2. Swelling of the retina, which signals the growth of new, abnormal blood vessels.

what is Histoplasmosis?   |  symptoms of Histoplasmosis   |  What is POHS? who is at risk for POHS?   |   how is POHS diagnosed?  |  treatment