Definition

Acute otitis media (AOM): acute middle ear cleft infection, with effusion and inflammatory symptoms. ^{AAP 2013}
AOM with perforation: new discharge through the tympanic membrane; pain commonly improves when the ear starts draining.
Recurrent AOM ^{AAP 2013}
Severe AOM: moderate or severe otalgia, pain for at least 48 hours, or temperature of 39 °C or above. ^{AAP 2013}
Otitis media with effusion (OME) is distinct from AOM. ^{NICE NG233}

Background

AOM usually follows a viral URTI. Eustachian tube dysfunction, immune status and infection contribute.

Coryzal symptoms commonly precede otalgia by 3 to 4 days.
More detail
Inflammation impairs middle ear ventilation and drainage. Children have less mature immunity and a shorter, more horizontal Eustachian tube.
Bacteria: Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pyogenes.
Viruses: RSV, rhinovirus, adenovirus, influenza and parainfluenza; viral and bacterial infection may coexist.
More detail
Intracranial suppuration may involve the Streptococcus anginosus group (historically S. milleri).

AOM predominantly affects children, with peak incidence at 6 to 12 months; adults are affected less often. ^{Kaur 2017}

Host: young age, family history, Down syndrome, cleft palate/craniofacial abnormality, immunodeficiency, primary ciliary dyskinesia and cystic fibrosis.
More detail
Common age range: 3 months to 3 years. Male sex is a weak association; reflux has been proposed but its role is uncertain.
Down syndrome, cleft palate and primary ciliary dyskinesia also warrant attention to persistent effusion and hearing; recurrent acute infections and OME need separate assessment.
Environment: nursery attendance, overcrowding, socioeconomic deprivation, tobacco smoke, bottle feeding and dummy use. Breastfeeding is protective.
More detail
In a prospective cohort of 615 children, 23% had experienced AOM by age 1 and 60% by age 3. ^{Kaur 2017}