The immune system is a complex system comprising many biological structures and processes that protect the body against disease. When a foreign protein, such as a virus or bacteria, is detected in the human body, a whole cascade of processes are activated that are intended to deactivate and remove that invader.

For reasons that are still not well understood, some people develop autoimmune diseases in which this process is activated against the person’s own cells. In order to treat autoimmune diseases, like myositis, doctors attempt to suppress some of these immune system processes with medications. Suppressing the immune system, however, places the patient at an increased risk for developing a serious infection.

For the vast majority of myositis patients, long-term immunosuppression is the only treatment for their muscle and skin symptoms. As a result, myositis patients must always be aware of prevention, early detection, and aggressive treatment of infection.

Signs and symptoms

Immunosuppression reduces the body’s normal response to infection, so you may notice that typical signs of infection, such as fever, will be weakened or delayed. Consult your primary care physician immediately if any of the following symptoms develop:

Urinary tract infection – feeling like you need to void frequently, burning with urination, urine is dark in color

Respiratory infection (cold, flu, sinusitis, bronchitis, pneumonia) – coughing, sneezing, nasal discharge, sputum production, fever, aching muscles or joints, malaise

Gastrointestinal infection – diarrhea, vomiting, fever, malaise

Skin infection, especially at the site of a cut or injury – redness, swelling, warm to touch, discharge, fever

Preventing infection

Prevention is by far the best treatment for infections. Patients and their care partners should always practice these infection prevention measures:

Wash your hands. Nothing prevents the spread of infection better than vigorous, frequent hand washing.

Pay attention to skin wounds. When you get a cut or scrape, wash the wound immediately with soap and water, and apply a bandage with antibiotic ointment. See your doctor if the area develops redness, swelling, foul-smelling discharge, or doesn’t show signs of healing.

Avoid contact with others who are sick. This may include avoiding crowds and close public spaces. It also includes using safe sex practices.

Avoid tick and mosquito bites, which may transmit infections such as Lyme disease and West Nile virus. Use insect repellant and cover your skin when out of doors during the summer, especially in the evening.

Avoid foods that may carry bacteria, including raw eggs, unpasteurized milk, and insufficiently cooked or raw meat. And always wash raw vegetables before eating them.

Be aware of unsafe drinking water, especially if you travel outside the US. Drink only bottled water while away, use it for rinsing your toothbrush, and don’t eat or drink anything that has not been cooked or peeled.

Discuss travel-related infections with a specialist if you plan a trip to developing countries where certain infectious diseases, such as yellow fever and malaria, are prevalent.

Vaccines are another way to prevent certain infections. A vaccine is a biological preparation that provides active acquired immunity to a particular disease. A vaccine often contains weakened or killed forms of the bacteria or virus that causes the disease. The vaccine stimulates the immune system to recognize that microorganism as a threat, to destroy it, and to recognize and destroy that microorganism if it encounters it in the future.

Patients with a suppressed immune system should never be given vaccines made with live or attenuated organisms, because it could cause the patient to become sick with the disease. The shingles vaccine and the nasal flu vaccine are live attenuated vaccines.

Immune-suppressed patients can get inactive vaccines, which include the flu shot (but not the nasal flu vaccine) and pneumococcal, meningococcal, and pertussis vaccines.

Other considerations

Prior to starting immunosuppressive treatment, it is recommended that patients be tested to see if they have tuberculosis (TB). If immunosuppression is started before the TB test is done, this treatment will also suppress the response to the TB test. If TB is present and untreated, this infectious disease may flare and spread to other areas of the body when immunosuppressive medications are started.

It is also recommended that testing for myositis specific antibodies (MSAs) be done prior to starting immunosuppressive treatment.

Patients with lung disease are at greater risk for developing an opportunistic infection called pneumocystis jiroveci pneumonia because of immunosuppression. These patients may be prescribed the antibiotic Bactrim to prevent this opportunistic infection of the lung.

Additional information about infection in myositis can be found in the Myositis Library section of this website.

Myositis and the risk of infection – video presentation by TMA medical advisor Dr. Mazen Dimachkie at the 2017 TMA Annual Patient Conference

Don’t bug me – Steering clear of infections – an article from the TMA quarterly magazine The OutLook