Mycetoma is a chronic infection that is caused by fungi or actinomycetes (bacteria that produce filaments, like fungi). Eventually, affected people experience massive swelling and hardening of the affected area; skin rupture; and formation of sinus tracts (holes) that discharge pus and grains filled with organisms. Some affected people have no discomfort while others report itching and/or pain. Mycetoma is rare in the United States, but is commonly diagnosed in Africa, Mexico and India. In these countries, it occurs most frequently in farmers, shepherds, and people living in rural areas. Frequent exposure to penetrating wounds by thorns or splinters is a risk factor.