Causes of Recurrent Ear Infections

Primary Infectious Pathway

Viral upper respiratory tract infections always precede acute otitis media, causing inflammation of the nasopharyngeal and eustachian tube epithelium 2
This viral infection leads to eustachian tube dysfunction, creating negative middle ear pressure and allowing secretions containing both viruses and bacteria from the nasopharynx to enter the middle ear 1
Bacteria and/or viruses can be detected in middle ear fluid in up to 96% of AOM cases (66% bacteria and viruses together, 27% bacteria alone, 4% virus alone) 1

Streptococcus pneumoniae, non-typeable Haemophilus influenzae, and Moraxella catarrhalis are the most common bacterial pathogens 1
Since introduction of pneumococcal conjugate vaccines, the distribution has shifted with H. influenzae becoming more prominent and non-vaccine serotypes of S. pneumoniae emerging 1
Streptococcus pyogenes accounts for less than 5% of cases 1

Eustachian tube dysfunction underlies most cases of otitis media, preventing proper middle ear ventilation and drainage 2
This dysfunction is particularly common in young children due to anatomic factors 2

Bacterial biofilms have been demonstrated in middle ears of patients with chronic and recurrent infections, protecting bacteria against antibiotics and immune responses 2
These biofilms form on middle ear mucosa and in middle ear effusion, making infections more difficult to eradicate 2

The American Academy of Pediatrics notes that the highest rates of AOM occur in children 1-4 years of age (61 new episodes per 100 children per year) is not mentioned, however, the age vulnerability relates to immature immune systems and eustachian tube anatomy 2

Day care attendance, older siblings, and passive smoke exposure increase infection frequency 4
Adenoid hypertrophy can contribute to recurrent infections by obstructing the eustachian tube 4
Allergic inflammation predisposes to bacterial superinfection 4

Primary immunodeficiency disorders should be considered when infections are repetitive, severe, or refractory to therapy 4
Up to 26% of children older than 2 years with invasive pneumococcal disease have an identifiable primary immunodeficiency 4