Pericarditis is usually a complication of viral infections caused by adenovirus and coxsackie virus. Less frequently, it can be caused by the polio, influenza or rubella viruses. Infections with bacteria can lead to bacterial pericarditis (also called purulent pericarditis). Some fungal infections can also produce pericarditis.

In addition, pericarditis can be associated with systemic diseases such as autoimmune disorders, rheumatic fever, tuberculosis, cancer, leukemia, kidney failure, HIV infections, AIDS and hypothyroidism. Heart disorders which can cause pericarditis include heart attack (see post-MI pericarditis) and myocarditis. Radiation therapy to the chest and medications that suppress the immune system can also sometimes induce this condition.

Pericarditis can also result from injury (including surgery) or trauma to the chest, esophagus or heart.

Quite often, the cause of pericarditis remains unknown; this disorder is called idiopathic pericarditis.

Pericarditis most often affects men ages 20 to 50, usually following respiratory infections. It can also occur in children, where it is most commonly caused by adenovirus or coxsackie virus.