Can Mycoplasma pneumoniae Cause a Dry Cough?
Yes, Mycoplasma pneumoniae definitively causes dry cough, which is one of its hallmark respiratory symptoms and typically presents as an initially non-productive, irritating, and intermittent cough. 1
Clinical Presentation of Cough in M. pneumoniae
The cough in M. pneumoniae infection characteristically begins as non-productive (dry), irritating, and intermittent in nature. 1
M. pneumoniae typically presents with a gradual onset of nonproductive cough, along with fever, headache, and arthralgia, rather than an abrupt onset. 2, 1, 3
The dry cough is a consistent feature across all age groups, though the overall clinical presentation is particularly characteristic in school-aged children and young adults. 1, 4
Duration and Evolution of Cough
In prospective studies of children with M. pneumoniae infection, the mean cough duration was approximately 23 days, making it a cause of both acute and chronic cough. 5
M. pneumoniae accounted for 26% of identified etiological agents in children with cough lasting more than 7 days but less than 100 days. 5
The infection can present as chronic cough (>28 days) without associated symptoms, especially when modified by antibiotics or vaccination status. 5
Associated Respiratory Findings
While the cough is typically dry, approximately 30% of patients will also develop wheezing on examination, which can lead to diagnostic confusion with asthma. 2, 1, 4
Crackles on auscultation are characteristic physical examination findings that accompany the cough. 2, 1, 4
The cough may be associated with other respiratory symptoms including sore throat and pharyngitis. 5, 3
Clinical Pitfalls
A critical caveat is that the presence of wheezing should not exclude M. pneumoniae from the differential diagnosis, as it occurs in nearly one-third of cases. 1, 4
The dry cough of M. pneumoniae can mimic viral respiratory syndromes and asthma, making clinical diagnosis challenging without serological confirmation. 6
No single physical examination finding, laboratory test, or radiographic sign is specific for M. pneumoniae infection, so the diagnosis often relies on the constellation of clinical features including the characteristic dry cough. 1