Acute otitis media (AOM) is a painful infection of the middle ear that most commonly results from a bacterial superinfection with Streptococcus pneumoniae, Haemophilus influenza, or Moraxella catarrhalis following a viral upper respiratory tract infection. AOM is a common infection in children under the age of 2 years and is characterized by an acute onset of symptoms (e.g., otalgia, fever, anorexia) with signs of middle ear inflammation (e.g., bulging tympanic membrane, erythema). Mild unilateral infections can be managed without antibiotics, as they are often self-limiting. Infections in children under 6 months, bilateral AOM, or severe symptoms are usually treated with oral antibiotics. Most children will experience at least one episode before the age of five; in children with recurrent AOM that causes frequent symptoms, myringotomy and insertion of tympanostomy tubes may be considered. The most common complication is acute mastoiditis, but facial palsy, labyrinthitis, and in rare cases, even intracranial abscesses may also occur.
- Highest incidence between 6–24 months of age 
Epidemiological data refers to the US, unless otherwise specified.
- The eustachian tube connects the middle ear with the nasopharynx and is lined with cilia, which drain the middle ear secretions into the nasopharynx.
- Obstruction/blockage of the eustachian tube (ET) → lack of ventilation and drainage of the middle ear →
Predisposing factors for ET obstruction
- Inflammation of the ET mucosa
- Viral URT infection (most common cause)
- Allergic rhinitis
- Mechanical obstruction of the ET
- Infants: shorter, narrower, and more horizontal ET → nasopharyngeal secretions easily reflux into the ET → more prone to developing AOM
- Inflammation of the ET mucosa
Common pathogens 
- General considerations
- Bacterial pathogens 
- Viral pathogens 
Risk factors for AOM 
General symptoms 
- Otalgia/earache, commonly described as throbbing pain
- Hearing loss in the affected ear
- Otorrhea in the case of a ruptured tympanic membrane (TM)
Typical presentation in infants 
- Incessant crying
- Refusal to feed (anorexia)
- Repeatedly touching the affected ear
- Fever and febrile seizures
Examination findings 
- Bulging tympanic membrane (TM) with loss of landmarks 
- Opacification and loss of light reflex
- Retracted and hypomobile TM
- Purulent/serosanguinous discharge in the external auditory canal or visible perforation
- Distinct erythema of the TM 
- Additional findings that may be present:
AOM is primarily a clinical diagnosis based on characteristic symptoms and otoscopic findings. Other causes of otalgia and hearing loss should be excluded (see “Differential diagnoses”). Pneumatic otoscopy or tympanometry should be used to confirm the presence of an effusion. 
Diagnostic criteria for AOM in children 
The diagnosis of AOM can be made if any of the following features are present: 
- Moderate to severe bulging of the tympanic membrane
- New onset of otorrhea not due to otitis externa
- New onset of otalgia AND mild bulging of the tympanic membrane
- Distinct erythema AND mild bulging of the tympanic membrane
Not routinely indicated; consider in severe infection or diagnostic uncertainty.
- CBC: Leukocytosis may be present.
Gram stain and culture of middle ear fluid 
- Indication: patients who do not respond to initial therapy, acutely ill patients, and patients with immune deficiencies 
- Typically acquired through tympanocentesis: the extraction of middle ear fluid through a small-gauge needle.
- Fluid should also be cultured if there is otorrhea from tympanostomy tubes or a perforated TM. 
- Blood cultures: indicated only in severe infection
- Rarely required unless there is clinical uncertainty and/or concerns of complications
- Suspected intracranial complications: MRI brain and temporal bone
- Suspected extracranial complications, e.g., mastoiditis: high-resolution CT temporal bone
Evaluation for effusion
Pneumatic otoscopy 
- Indications: clinical uncertainty for AOM and to confirm the presence of middle ear effusion
- Characteristic finding: hypomobility of the tympanic membrane 
- Tympanometry 
- Screen patients for acute complications such as mastoiditis and labyrinthitis and treat if present.
- Provide analgesia as needed.
- Consider antibiotic therapy based on the patient's age and clinical features.
- Reassess all patients managed conservatively after 48–72 hours; if there is no improvement, give antibiotics.
- Consult ENT for adults with recurrent AOM or persistent otitis media with effusion. 
Uncomplicated AOM is self-limiting in most children (∼ 80%). 
- Outpatient observation and surveillance of symptoms for 48–72 hours
- Oral analgesia 
- No sufficient evidence to support the routine use of opioids, decongestants, antihistamines, steroids 
Many patients with AOM can be treated conservatively. 
- Topical antibiotics are typically reserved for patients with AOM and tympanostomy tubes (see “Special situations”) or those with chronic suppurative otitis media. 
- Treatment failure is common (due to drug resistance and viral coinfection); If initial treatment is unsuccessful, consider tympanocentesis to help guide further therapy.
- Typical duration of first-line therapy 
- Children < 2 years OR any child with severe symptoms: 10 days
- Children ≥ 2 years AND no severe symptoms: 5–7 days
- Children 
- Adults: Antibiotics (e.g., amoxicillin) are typically given to prevent complications. 
|Empiric antibiotic therapy for acute otitis media |
|No antibiotic use in previous 30 days||Antibiotic use in previous 30 days||Penicillin allergy|
H.influenzae and S.pneumoniae show limited sensitivity towards macrolides and trimethoprim/sulfamethoxazole; these antibiotics should only be used for patients with a proven history of type I hypersensitivity to penicillin. 
- Not routinely indicated in acute AOM
- Consider for patients with treatment failure or recurrent infection.
- Myringotomy 
- Myringotomy with tympanostomy tube insertion 
AOM with perforated tympanic membrane
- Usually (> 90%) heals spontaneously with systemic antibiotic therapy (See “Empiric antibiotic therapy for AOM.”) 
- There is no added advantage of topical antibiotics for AOM with TM perforation unless tympanostomy tubes are present. 
- The ear should be kept clean and dry until the TM has fully healed. 
Patients with tympanostomy tubes 
- Increased discharge indicates acute infection.
- Usually caused by the same spectrum of bacterial pathogens, but Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermis are also possible
- Can be treated with topical antibiotics for 7 days (e.g., ofloxacin , ciprofloxacin/dexamethasone 
- If there are complications or systemic illness, oral antibiotics (normally amoxicillin/clavulanic acid ) can be given. 
Otitis media can spread to affect other local structures (e.g., mastoiditis, labyrinthitis, facial nerve palsy, perforated tympanic membrane) or the intracranial cavity (e.g., meningitis, cerebral venous thrombosis, otogenic abscess).
Risk factors for complications
Complications are rare and are usually only seen in the following cases:
- Highly virulent bacteria (e.g., Group A ß-hemolytic streptococci)
- Immunocompromised patients
- Inadequate dose/duration of antibiotics
- Bacterial drug resistance
- Definition: inflammation of the mastoid air cells
- Epidemiology: : most commonly occurs in children < 2 years 
- Pathophysiology: infection spreads from the middle ear cavity into the mastoid, which is a closed bony compartment → collection of pus under tension and hyperemic resorption of the bony walls → destruction of the air cells (coalescent mastoiditis) → mastoid becomes a pus-filled cavity (empyema mastoid)
Clinical features of mastoiditis
- Signs and symptoms
- Otoscopy findings: may be normal
Diagnostics for mastoiditis 
Indications for imaging
- Symptoms that do not improve after 48 hours of treatment.
- Suspected intracranial complication
- Planned surgical interventions
- CT scan of the temporal bone: Initial imaging study (if indicated)
MRI brain and temporal bone  Consider as initial modality in children due to lack of ionizing radiation 
- More sensitive for intracranial infectious complications
- Characteristic findings include increased fluid signal intensity in mastoid air cells.
X-ray of the mastoid 
- Early stage: The air cells appear cloudy and indistinct.
- Advanced stage: A cavity can be seen in the mastoid.
Acute mastoiditis 
- Provide analgesia as needed.
- Screen for symptoms of sepsis and/or meningitis.
Start empiric antibiotic therapy with levofloxacin or ceftriaxone
- If episode is secondary to an acute exacerbation of chronic otitis media: surgical debridement of auditory canal AND start antibiotic treatment with:
- Surgical interventions
- Refer to ENT for admission and consideration of surgery. 
- Chronic mastoiditis
- Postauricular abscess
- Bezold abscess
- Infection spreads to the zygomatic air cells (located at the zygomatic root)
- Causes swelling in front of and above the auricle
- Brain abscess
- Etiology: Inflammation spreads to the inner ear (labyrinth) through the round window.
- Clinical features
- Epidemiology: Rare complication in the antibiotic era
- Etiology: unclear
- Clinical features: lower motor neuron paralysis of cranial nerve VII
- Route of spread: direct spread of infection from the middle ear through the destroyed bone overlying the dura or through an emissary vein
- Clinical features
- Diagnostics: MRI/contrast-enhanced CT
- Treatment: IV antibiotics + drainage + mastoidectomy
Other intracranial complications
We list the most important complications. The selection is not exhaustive.