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What causes a baby's runny nose?
Medical expert of the article
Last reviewed: 04.07.2025
The main causative agents of acute nasopharyngitis (runny nose) are viruses. These are primarily rhinoviruses (45% of all cases of the disease), less often - PC virus, ECHO viruses, coronaviruses, parainfluenza viruses and adenoviruses, as well as influenza B viruses.
Bacterial pathogens are less common, but still cause nasopharyngitis (runny nose). The most common of these are Mycoplasma pneumoniae, much less common is Chlamydoia pneumoniae, and even less common is Ch. psittaci.
Pathogenesis of acute nasopharyngitis
Acute nasopharyngitis (runny nose) is an acute inflammation of the mucous membrane of the nasal passages, as well as the mucous membrane and lymphoid elements of the posterior pharyngeal wall, accompanied by tissue edema and increased secretion of mucous secretions, or, conversely, increased dryness of the mucous membranes.