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Atypical pneumonia

  • Definition

    Atypical pneumonia refers to pneumonia caused by certain bacteria, including Legionella pneumophila, Mycoplasma pneumoniae, and Chlamydophila pneumoniae.

    Pneumonia is a condition in which there is an infection of the lung.


    Alternative Names

    Walking pneumonia; Chlamydophila pneumoniae; Community-acquired pneumonia - atypical


    Causes, incidence, and risk factors

    Mycoplasma pneumonia is a type of atypical pneumonia. It is caused by the bacteria M. pneumoniae. It typically affects people younger than age 40. For more information on this type of pneumonia, see: Mycoplasma pneumonia

    Pneumonia due to chlamydia-related bacteria occurs year round and accounts for 5 - 15% of all pneumonias. It is usually mild.

    Pneumonia due to Legionella is seen more often in middle-aged and older adults, smokers, and those with chronic illnesses or a weak immune system.

    See also: Legionnaire's disease