Skin lesion of Histoplasmosis

Definition:

A symptom of Histoplasmosis, an infection caused by inhaling the spores of the fungus Histoplasma capsulatum, which are in bird and bat droppings and are common along river valleys

Causes, incidence, and risk factors:

Histoplasmosis is caused by a fungus found in the central and eastern U.S., eastern Canada, Mexico, Central America, South America, Africa, and southeastern Asia. The fungus has been linked to exposure to birds, bird feathers, and bats.

Histoplasmosis, a type of fungus, exists as a spore in the soil in endemic areas. Exposure is usually through inhalation of the spore. The spore germinates into the fungus which can cause primary pulmonary histoplasmosis (a type of pneumonia) or spreads from the lungs to other areas of the body.

Most cases are mild or asymptomatic. The symptoms most commonly occur as a nonspecific respiratory infection similar to a cold or flu. It can also occur as an acute or progressive disorder, as disseminated (widespread) disease, or as a chronic disorder. The acute disease may occur in epidemics, with illness lasting for 1 to 6 months, but it is rarely fatal. The acute progressive Histoplasmosis continues to worsen and is often fatal within 6 weeks or less. It involves the liver, spleen, and all the organs of the body. Skin lesions are common with progressive Histoplasmosis.

Skin lesions may also occur with disseminated and chronic Histoplasmosis. The disseminated disease commonly occurs in persons with immune system disorders such as AIDS and is often rapidly fatal. The chronic disease may occur in immunosuppressed persons or in elderly persons with COPD and mild immune compromise, and usually confines symptoms to the lungs until it is in its terminal stages. The chronic or disseminated disease can also occur in people with normal immune systems although this is rare.

The associated skin lesion usually presents as a lesion on the mouth or inner cheek. Like other mouth ulcers, it may interfere with the ability to eat and drink because of discomfort.