Clinical features include: (1)
- peak rate of infection in autumn and early winter
 - initial influenza-like disease with headache, fever, malaise, myalgia, diarrhoea and fatigue - often develop several days before the onset of respiratory problems; the malaise and fatigue may persist for long after the acute illness
 - cough - initially dry and often insignificant; usually becomes productive with a mucoid and purulent sputum; often paroxysmal, disturbing sleep; may be absent in one-third of cases
 - isolated crackles or areas of wheezing may be heard over one of the lower lobes
 - subsegmental atelectasis and small effusions often detectable in the absence of prominent chest symptoms
 - wide variety of respiratory and non-respiratory complications
 
1. Yin YD, Zhao F, Ren LL, et al. Evaluation of the Japanese Respiratory Society guidelines for the identification of Mycoplasma pneumoniae pneumonia. Respirology. 2012 Oct;17(7):1131-6.