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Mycoplasma pneumoniae Infections

Some lung infections, including many cases of mild pneumonia (also referred to as walking pneumonia), are caused by an organism called Mycoplasma pneumoniae. It is spread from person to person in secretions such as phlegm from the respiratory passages and has an incubation period of 2 to 3 weeks. Transmission of this organism usually takes place through close contact. Outbreaks have occurred and are common in summer camps and colleges, as well as within households among family members.

While M pneumoniae infections are uncommon in children younger than 5 years, they are a leading cause of pneumonia in school-aged children and young adults. Community-wide epidemics of this illness occur every 4 to 7 years.

Signs and Symptoms

M pneumoniae infections cause symptoms that are usually mild. They can get worse over time in some children. The most common symptoms are

  • Bronchitis
  • Upper respiratory tract infections, including sore throats and, at times, ear infections

Children with this infection may also have a high fever, long-lasting weakness, and in some cases, headaches and a rash. Their cough can change from a dry cough to a phlegmy one. On rare occasions, youngsters may develop croup and a sinus infection (sinusitis).

When to Call Your Pediatrician

If these symptoms, including a fever, last for more than a few days, contact your pediatrician.

How Is the Diagnosis Made?

Your pediatrician will give your child a physical examination. The doctor may order blood tests for antibodies to M pneumoniae or cold agglutinins, which are a special type of antibody. Special tests are being developed to identify the organism in throat and respiratory samples, but these are not generally available yet.


In most cases, the bronchitis and upper respiratory tract illnesses associated with M pneumoniae infections are mild and get better on their own without antibiotic treatment. However, antibiotics such as erythromycin, azithromycin, or doxycycline may be given for more serious symptoms associated with pneumonia and ear infections.

What Is the Prognosis?

This infection often causes wheezing in children with asthma or reactive airways. Most people fully recover from this infection, even when antibiotics are not used. The death rate is quite low.

Last Updated
Immunizations & Infectious Diseases: An Informed Parent's Guide (Copyright © 2006 American Academy of Pediatrics)
The information contained on this Web site should not be used as a substitute for the medical care and advice of your pediatrician. There may be variations in treatment that your pediatrician may recommend based on individual facts and circumstances.
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