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What causes acute sinusitis in children?
Last reviewed: 06.07.2025
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In the etiology of acute sinusitis in children over 3-4 years of age, the leading role is played by pneumococci (up to 40% of cases), followed by non-typeable Haemophilus influenzae (up to 10-12% of cases), a slightly lesser role is played by Staphylococcus aureus and Staphylococcus epidermidis, Moraxella catarrhalis and pyogenic streptococcus.
In infants and young children, the etiology of acute sinusitis, which occurs as acute ethmoiditis and acute sinusitis, is different. In newborns and children in the first half of life, the leading role is played by Staphylococcus aureus and Staphylococcus epidermidis. The second most common are enteropathogenic bacilli such as Escherichia coli and Klebsiella. Acute sinusitis can also be caused by pyogenic streptococcus. Pneumococcus, Haemophilus influenzae and Moraxella catarrhalis are practically not encountered at this age due to the immunity to these pathogens passively transmitted by the child's mother. Only by the age of one year does their role as a cause of acute sinusitis gradually increase and after 2-3 years they are the leaders as pathogens of acute sinusitis.
In children aged 6-7 months to 4-5 years, respiratory viruses play a significant role in the etiology of acute sinusitis - rhinoviruses, enteroviruses, parainfluenza viruses and respiratory syncytial viruses (RS viruses).
Pathogenesis of acute sinusitis
Respiratory viruses and bacteria, causing inflammation of the mucous membrane of the nasal cavities, contribute to a decrease in local anti-infective protection and, due to swelling of the mucous membrane of the nasal cavities, cause obstruction of the passages and, in connection with this, accumulation of exudate in the nasal cavities. Violation of the passage of exudate is also facilitated by spines and ridges of the nasal septum, hypertrophy of the middle and lower nasal conchae, hyperplasia of the mucous membrane and polyps.
All this leads to a disruption of ventilation of the paranasal sinuses. The disruption of the passage of exudate serves as a factor contributing to the rapid proliferation of bacterial microflora and the transition to a purulent process.