Mycoplasma epidemic was associated with more severe cases, but few extrapulmonary manifestations

Background Mycoplasma pneumoniae is a common microbe causing respiratory infections and it may also produce symptoms in other organ systems. There is very limited research on these extrapulmonary manifestations.

Methods We conducted a retrospective medical record-based study of patients diagnosed with mycoplasma infection (n=220) who were treated at a university hospital between 2010 and 2024. We compared data from patients in 2010–2023 with data of those infected during the 2024 epidemic.

Results The mean age of the patients was 28.9 years, and 70.5% of them had pneumonia. Extrapulmonary symptoms were observed in approximately 22% of patients and in 31% of those requiring intensive care or high-dependency care. The most common extrapulmonary manifestations were dermatological or mucosal symptoms. Extrapulmonary symptoms were not associated with asthma or atopy. During the 2024 epidemic, 8% of the patients required intensive care or high dependency monitoring, and 12% had extrapulmonary symptoms, whereas the corresponding percentages in previous years were 5% and 29%.

Conclusions Mycoplasma pneumoniae infections and their extrapulmonary manifestations occur most commonly in children and young adults. During the large epidemic in 2024, extrapulmonary manifestations were less common than in previous years.

Kiia Tefke, Juulia Ovaskainen, Marjo Renko, Sari Hämäläinen