Often, the exact cause of an individual case of myocarditis isn't identified. However, there are numerous potential causes of myocarditis, such as:

  • Viruses. Many viruses are commonly associated with myocarditis, including coxsackievirus B, which can cause symptoms similar to a mild case of flu; the viruses that cause the common cold (adenovirus); parvovirus B19, which causes a rash called fifth disease; and herpes simplex virus.

    Gastrointestinal infections (echoviruses), mononucleosis (Epstein-Barr virus) and German measles (rubella) also are potential causes of myocarditis. Myocarditis is also common in people with HIV, the virus that causes AIDS.

  • Bacteria. Numerous bacteria can cause myocarditis, including staphylococcus, streptococcus, the bacteria that causes diphtheria and the tick-borne bacterium responsible for Lyme disease.
  • Parasites. Among these are such parasites as Trypanosoma cruzi and toxoplasma, including some that are transmitted by insects and can cause a condition called Chagas disease. This disease is more prevalent in Central and South America than in the United States, but it can occur in travelers and in immigrants from that part of the world.
  • Fungi. Some yeast infections (such as candida), molds (such as aspergillus) and other fungi (such as histoplasma, often found in bird droppings) can sometimes cause myocarditis.

Myocarditis also sometimes occurs if you're exposed to:

  • Medications or illegal drugs that might cause an allergic or toxic reaction. These include antibiotics, such as penicillin and sulfonamide drugs; some anti-seizure medications; and some illegal substances, such as cocaine.
  • Chemicals or radiation. Exposure to certain chemicals, such as carbon monoxide, and radiation can sometimes cause myocarditis.
  • Other diseases. These include disorders such as lupus, Wegener's granulomatosis, giant cell arteritis and Takayasu's arteritis.
Oct. 24, 2015