What Causes Formation of Granuloma?

A granuloma is a patch of inflamed tissue that has various causes, depending on its location in the body, but is most often caused by a fungal infection, according to the Mayo Clinic. Some common types of granuloma include lung granuloma, granuloma annulare and hepatic granuloma.

In the United States, the most common cause of lung granulomas is the fungal infection histoplasmosis, notes the Mayo Clinic. People who have pulmonary histoplasmosis and a lung granuloma most likely got infected from spending time in the Ohio Valley or the upper Midwest. Because the signs and symptoms of the disease are rare, people do not suspect that they have it.

Granuloma annulare is a skin condition that is characterized by bumps on the skin and has no known cause, according to the Mayo Clinic. In some people, medications or skin injuries can trigger the condition. Other triggers include insect bites, infections such as hepatitis, tuberculin skin tests and vaccinations. Some types of skin granulomas occur mostly in adults, while others typically affect children.

A hepatic granuloma, which is a liver granuloma, has many causes, with the most common being drugs and infections, notes Merck Manual. Tuberculosis and schistosomiasis are the most common infections that cause these granulomas, while fungal and viral infections are less common. Disorders such as sarcoidosis are also responsible for hepatic granulomas, as are liver disorders such as primary biliary cirrhosis.