What is the most common cause of pericarditis?

The most common cause of pericarditis is viral infection. Viral pericarditis often follows a viral illness, such as a respiratory tract infection, leading to inflammation of the pericardial sac surrounding the heart. The types of viruses most commonly associated with pericarditis include those in the echovirus family, Coxsackie viruses, and sometimes other viral infections like influenza or HIV.

While bacterial infections can also cause pericarditis, they are less frequent than viral causes. Fungal infections are quite rare and typically occur in immunocompromised patients. Autoimmune disorders, such as systemic lupus erythematosus or rheumatoid arthritis, can lead to pericarditis, but they are not the most common cause. Viral agents predominate in typical cases of pericarditis, making them the leading cause in clinical scenarios.