What is mycoplasma pneumonia?

Mycoplasma pneumonia (MP) is a contagious respiratory infection that spreads easily through contact with respiratory fluids. It can cause epidemics.

MP is known as an atypical pneumonia and is sometimes called “walking pneumonia.” It spreads quickly in crowded areas, such as schools, college campuses, and nursing homes. When an infected person coughs or sneezes, moisture containing the MP bacteria is released into the air. Uninfected people in their environment can easily breathe the bacteria in.

Up to one-fifth of all lung infections that people develop in their community (outside of a hospital) are caused by Mycoplasma pneumoniae bacteria. The bacteria can cause tracheobronchitis (chest colds), sore throats, and ear infections as well as pneumonia.

A dry cough is the most common sign of infection. Untreated or severe cases can affect the brain, heart, peripheral nervous system, skin, and kidneys and cause hemolytic anemia. In rare cases, MP is fatal.

Early diagnosis is difficult because there are few unusual symptoms. As MP progresses, imaging and laboratory tests may be able to detect it. Doctors use antibiotics to treat MP. You may need intravenous antibiotics if oral antibiotics don’t work or if the pneumonia is severe.

MP symptoms are different from those of typical pneumonia caused by common bacteria, such as Streptococcus and Haemophilus. Patients usually do not have severe shortness of breath, high fever, and a productive cough with MP. They more commonly have low-grade fever, dry cough, mild shortness of breath especially with exertion, and fatigue.

Learn more: Pneumonia »

The Mycoplasma pneumonia bacterium is one of the most recognized of all human pathogens. There are over 200 different known species. Most people with respiratory infections caused by Mycoplasma pneumoniae don’t develop pneumonia. Once inside the body, the bacterium can attach itself to your lung tissue and multiply until a full infection develops. Most cases of mycoplasma pneumonia are mild.

In many healthy adults, the immune system can fight off MP before it grows into an infection. Those most at risk include:

  • older adults
  • people who have diseases that compromise their immune system, such as HIV, or who are on chronic steroids, immunotherapy, or chemotherapy
  • people who have lung disease
  • people who have sickle cell disease
  • children younger than age 5

MP may mimic an upper respiratory infection or common cold rather than a lower respiratory infection or pneumonia. Again, these symptoms usually consist of the following:

  • dry cough
  • persistent fever
  • malaise
  • mild shortness of breath

In rare cases, the infection can become dangerous and damage the heart or central nervous system. Examples of these disorders include:

  • arthritis, in which the joints become inflamed
  • pericarditis, an inflammation of the pericardium that surrounds the heart
  • Guillain-Barré syndrome, a neurological disorder that can lead to paralysis and death
  • encephalitis, a potentially life-threatening inflammation of the brain
  • kidney failure
  • hemolytic anemia
  • rare and dangerous skin conditions such as Stevens-Johnson syndrome and toxic epidermal necrolysis
  • rare ear problems such as bullous myringitis

MP usually develops without noticeable symptoms for the first one to three weeks after exposure. Early-stage diagnosis is difficult because the body doesn’t instantly reveal an infection.

As previously mentioned, the infection can manifest outside of your lung. If this happens, signs of infection may include the breakup of red blood cells, a skin rash, and joint involvement. Medical testing can show evidence of an MP infection three to seven days after the first symptoms appear.

In order to make a diagnosis, your doctor uses a stethoscope to listen for any abnormal sounds in your breathing. A chest X-ray and a CT scan may also help your doctor to make a diagnosis. Your doctor may order blood tests to confirm the infection.


Antibiotics are the first line of treatment for MP. Children get different antibiotics than adults to prevent potentially dangerous side effects.

Macrolides, the first choice of antibiotics for children, include:

  • erythromycin
  • clarithromycin
  • roxithromycin
  • azithromycin

Antibiotics prescribed for adults include:

  • doxycycline
  • tetracycline
  • quinolones, such as levofloxacin and moxifloxacin


Sometimes antibiotics alone are not enough and you have to be treated with corticosteroids to manage the inflammation. Examples of such corticosteroids include:

  • prednisolone
  • methylprednisolone

Immunomodulatory therapy

If you have severe MP, you may need other “immunomodulatory therapy” in addition to corticosteroids, such as intravenous immunoglobulin or IVIG.

The risk of contracting MP peaks in the fall and winter months. Close or crowded places make it easy for the infection to transmit from person to person.

To lower your risk of infection, try the following:

  • Get six to eight hours of sleep per night.
  • Eat a balanced diet.
  • Avoid people with symptoms of MP.
  • Wash your hands before eating or after interacting with infected people.

In general, children are more susceptible to infections than adults. This is aggravated by the fact that they’re often surrounded by large groups of other, possibly infectious, children. Because of this, they may be at a higher risk for MP than adults. Take your child to the doctor if you notice any of these symptoms:

  • persistent low-grade fever
  • cold or flu-like symptoms that persist longer than 7-10 days
  • a persistent dry cough
  • wheezing while breathing
  • they have fatigue or don’t feel well and it doesn’t get better
  • chest or stomach pain
  • vomiting

To diagnose your child, their doctor may do one or more of the following:

  • listen to your child’s breathing
  • take a chest X-ray
  • take a bacterial culture from their nose or throat
  • order blood tests

Once your child is diagnosed, their doctor may prescribe an antibiotic for 7-10 days to treat the infection. The most common antibiotics for children are macrolides, but their doctor may also prescribe cyclines or quinolones.

At home, make sure your child doesn’t share dishes or cups so that they don’t spread the infection. Have them drink plenty of fluids. Use a heating pad to treat any chest pains they experience.

Your child’s MP infection will usually clear up after two weeks. However, some infections can take up to six weeks to fully heal.

In some cases, an MP infection can become dangerous. If you have asthma, MP can make your symptoms worse. MP can also develop into a more severe case of pneumonia.

Long-term or chronic MP is rare but may cause permanent lung damage, as suggested in one study performed on mice. In rare cases, untreated MP can be fatal. See your doctor right away if you experience any symptoms, especially if they last for more than two weeks.

M. pneumoniae is the second most common cause of pneumonia-related hospitalizations in adults, according to the Centers for Disease Control and Prevention.

Most people develop antibodies to MP after an acute infection. The antibodies protect them from becoming infected again. Patients who have a weak immune system, such as those with HIV and those who are treated with chronic steroids, immunomodulators, or chemotherapy, may have difficulty fighting off an MP infection and are at higher risk for reinfection in the future.

For others, symptoms should subside one to two weeks after treatment. A cough may linger, but most cases resolve with no lasting consequences within four to six weeks. See your doctor if you continue to experience severe symptoms or if the infection is interfering with your daily life. You may need to seek treatment or a diagnosis for any other conditions that might have been caused by your MP infection.