Signs and Symptoms

In general, Chlamydia pneumoniae infection is a mild illness that most commonly causes an upper respiratory tract infection. These upper respiratory tract infections can include a sore throat or an ear or sinus infection. Common symptoms include:

  • Runny or stuffy nose
  • Fatigue (feeling tired)
  • Low-grade fever
  • Hoarseness or loss of voice
  • Sore throat
  • Slowly worsening cough that can last for weeks or months
  • Headache

C. pneumoniae can also cause lower respiratory tract infections like bronchitis (inflammation or swelling of the airways that carry air to the lungs) and pneumonia (lung infection). Some reports say that people with pneumonia caused by C. pneumoniae are more likely to have laryngitis (inflammation of the voice box) compared to people with other types of bacterial pneumonia.

It can take 3 to 4 weeks for symptoms to appear after someone has been exposed to the bacteria. Symptoms can also continue for several weeks after they start.

Page last reviewed: November 15, 2021