Heart Inflammation Causes and Risk Factors

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Infections

Viral, bacterial, fungal, and parasitic infections can cause heart inflammation.

• Viral infections are the most common cause of myocarditis and pericarditis. These may include SARS-CoV-2 (the virus that causes COVID-19), adenovirus, coxsackievirus (including hand, foot, and mouth disease), herpes virus, and influenza (flu) virus and parvovirus B19 (which causes an infection common in children known as fifth disease). Viruses may infect the heart muscle tissue, causing the body’s immune system to react.

• Bacteria are the most common cause of endocarditis, which occurs when bacteria and blood cells form clumps, typically on the heart valves. In most developed countries Staphylococcus aureus (staph infection) is the most common type of bacteria that causes endocarditis. Bacteria can enter the blood in many ways, including during a medical or dental procedure or through intravenous drug use. Streptococcus (strep) bacteria can also cause endocarditis, but this is more common in less developed countries. Pericarditis caused by bacteria is not common in the United States.
• Fungi are rare causes of myocarditis and pericarditis. Most commonly, fungal endocarditis is caused by either Candida (yeast) or Aspergillus (mold). These infections are more common in people who have weakened immune systems from conditions such as HIV, cancer, or diabetes.
• Parasites are another infectious cause of myocarditis, such as the parasite that causes Chagas disease, a serious health problem in Latin America. The parasite can specifically affect the heart at the time of infection and may lead to the need for a pacemaker.

Autoimmune diseases

Autoimmune diseases such as rheumatoid arthritis and lupus may cause pericarditis or myocarditis. They can also damage the heart valves, which can lead to endocarditis.

Medicines

Medicines can cause side effects that may lead to myocarditis, pericarditis, or both. These include:

• Antibiotics, such as penicillin
• Antidepressants, such as tricyclic antidepressants
• Benzodiazepines, known as tranquilizers, such as lorazepam and diazepam
• Diuretics, which are medicines, such as furosemide and hydrochlorothiazide, that help your body get rid of extra fluid
• Heart medicines, such as amiodarone, hydralazine, methyldopa, and procainamide
• Psychiatric medicines, such as clozapine and lithium
• Seizure medicines, such as phenytoin
• Vaccines, which may cause allergic reactions leading to myocarditis, although this is rare
• Weight-loss medicines, such as phentermine-fenfluramine (phen-fen)

Age

Different age groups are at risk for different types of heart inflammation.

• Although they can affect all ages, myocarditis and pericarditis occur more often in young adults. Pericarditis also commonly affects middle-aged adults.
• Older adults are more at risk for endocarditis caused by bacteria.

Sex

Heart inflammation from endocarditis, myocarditis, and pericarditis is more common in men than in women. This is true except when the inflammation is caused by autoimmune diseases, such as lupus and rheumatoid arthritis, which are more common in women.

Endocarditis and pericarditis occur twice as often in men as in women.

Family history and genetics

Genetics play a role in the risk of developing all three types of heart inflammation.

• Your genes may be partly responsible for how your body responds to infection and inflammation and whether you develop myocarditis or pericarditis.
• People who have structural or congenital heart defects, such as problems with the heart valves, may be at higher risk for infections that can cause endocarditis.
• Certain inherited conditions can affect your risk of heart inflammation. For example, you may be at higher risk for myocarditis and pericarditis if you have familial Mediterranean fever or tumor necrosis factor receptor-associated periodic syndrome (TRAPS). These rare conditions affect how the body controls inflammation.

Environment

Chagas disease, common in Latin America, can cause acute and chronic myocarditis. It is caused by a parasite that is spread by certain types of insects. Endocarditis caused by Streptococcus bacteria is more common in less developed countries.

Lifestyle choices

Your risk may be higher if you:

• Drink too much alcohol, which could also lead to reduced heart function and heart failure
• Use cocaine, amphetamines, or intravenous recreational drugs
• Have poor dental health

Medical conditions

Medical conditions that can increase your risk include:

• Diabetes, which can make you more likely to develop infections
• Eating disorders such as anorexia
• HIV/AIDS, which may lead to myocarditis from causes such as treatment, viral, bacterial, or fungal infections, and nutritional deficiencies
• Skin disorders, such as burns or infections that occur often.

Procedures to treat other medical conditions also carry a risk of infection, which can lead to heart inflammation. These include implanting a pacemaker or defibrillator in the heart, or getting treatment for heart problems.

You may not be able to prevent heart inflammation.

If you have risk factors for endocarditis, your doctor may recommend steps to prevent bacterial growth on the endocardium.

• Avoid using recreational intravenous (IV) drugs.
• Wash your hands and skin regularly and wash cuts or scrapes right away to help prevent infection.
• Brush and floss your teeth every day and see your dentist regularly.

Many causes of myocarditis and pericarditis are difficult or impossible to avoid or prevent. Managing some risk factors for diseases such as HIV and avoiding substances such as amphetamines and cocaine may help prevent myocarditis.

Fact Sheet

Taking Care of Our Hearts, Together

Learn more about how healthy lifestyle changes can help prevent heart disease.

View the fact sheet