Chronic otitis media (COM)

Definition

Classification

1. Modern clinical classification

1. Active COM
   • Active inflammation with discharge.
2. Inactive COM
   • Dry ear but residual pathology remains, for example perforation or retraction pocket, with potential to reactivate.
3. Healed COM
   • Healed tympanic membrane with no active disease or significant potential for reactivation.

2. Traditional CSOM classification

• Tubotympanic disease
  • Central perforation of pars tensa.
  • Usually mucosal disease.
  • Less likely to cause serious complications, but may impair hearing and discharge recurrently.
• Atticoantral disease
  • Attic or marginal perforation, often with cholesteatoma.
  • Bone-eroding and potentially dangerous.
  • Requires specialist surgical assessment.

3. Cholesteatoma

Etiology and predisposing factors

Pathogenesis

• Recurrent or inadequately resolved acute otitis media
• Persistent middle-ear effusion
• Eustachian tube dysfunction, causing negative middle-ear pressure, tympanic membrane retraction, atelectasis, and retraction pockets
• Persistent perforation allowing repeated contamination of the middle ear
• Chronic infection and biofilm formation
• Development of cholesteatoma from a retraction pocket or epithelial migration through a perforation

Risk factors

• Childhood and recurrent upper respiratory infections
• Adenoid hypertrophy, chronic rhinitis, sinus disease
• Cleft palate or craniofacial anomalies
• Poor socioeconomic conditions, overcrowding, malnutrition
• Water contamination or repeated water entry into a perforated ear
• Previous ear trauma or ear surgery
• Immunodeficiency and poorly controlled diabetes
• Smoking exposure

Microbiology

• Pseudomonas aeruginosa
• Staphylococcus aureus
• Proteus species
• Klebsiella species
• Anaerobes, particularly in infected cholesteatoma

Clinical features

Symptoms

• Persistent or recurrent ear discharge, often mucopurulent
• Conductive hearing loss
• Ear blockage or tinnitus
• Usually little pain in uncomplicated disease
• Foul-smelling scanty discharge suggests cholesteatoma
• Vertigo, facial weakness, severe headache, fever, or altered sensorium suggest complications

Otoscopic findings

• Central perforation of pars tensa
• Inflamed, oedematous middle-ear mucosa
• Mucopus or mucoid discharge
• Granulations or aural polyp may be present
• Ossicular erosion can occur in longstanding disease

• Pars flaccida or posterosuperior retraction pocket
• White keratin debris
• Attic or marginal perforation
• Granulations, aural polyp, scutum erosion
• Foul-smelling discharge
• Aural polyp in a chronically discharging ear should be regarded as cholesteatoma until excluded. K J Lee's Essential Otolaryngology, p. 446.

Complications

• Acute mastoiditis
• Mastoid abscess
• Facial nerve palsy
• Labyrinthitis or labyrinthine fistula causing vertigo
• Petrositis
• Ossicular destruction and worsening hearing loss

• Meningitis
• Extradural or subdural abscess
• Temporal lobe or cerebellar abscess
• Lateral sinus thrombosis

Investigations

1. Otoscopy, otomicroscopy, or otoendoscopy
   • Define perforation, retraction pocket, keratin debris, granulation, and cholesteatoma.
   • Suction clearance of debris may reveal concealed disease.
2. Pure-tone audiometry
   • Usually shows conductive hearing loss.
   • Mixed loss may occur with longstanding disease or labyrinthine involvement.
   • Speech audiometry as indicated.
3. Tympanometry
   • Useful when the tympanic membrane is intact or in assessing middle-ear mechanics.
   • Not useful in a large perforation in the usual way.
4. Ear swab for microscopy, culture, and sensitivity
   • Indicated in persistent, recurrent, severe, or treatment-resistant discharge.
5. High-resolution CT temporal bone
   • Indicated for suspected cholesteatoma, complications, surgical planning, recurrent disease, facial palsy, or vertigo.
   • Assesses mastoid pneumatization, ossicular erosion, scutum erosion, tegmen, facial canal, and labyrinth.
6. MRI brain/temporal bone with contrast and diffusion-weighted imaging
   • For suspected intracranial complications.
   • Useful for detecting or following residual/recurrent cholesteatoma.
7. Biopsy
   • Consider for granulation tissue or aural polyp that does not resolve with appropriate topical treatment, to exclude malignancy.

Management

Principles

A. General measures

• Keep the ear dry: avoid swimming and water entry.
• Treat associated nasal allergy, rhinosinusitis, or upper respiratory disease.
• Counsel against inserting cotton buds, oils, or unprescribed ear drops.
• Assess hearing and its educational, occupational, and communication impact.

B. Active mucosal COM / CSOM

1. Aural toilet
   • Microsuction or dry mopping to remove pus, debris, and granulation tissue.
   • This improves penetration of topical treatment.
2. Topical antibiotic ear drops
   • Culture-directed where possible.
   • Non-ototoxic topical fluoroquinolone preparations are commonly preferred when a perforation is present.
   • Add topical corticosteroid only when clinically appropriate for marked inflammation or granulations.
3. Systemic antibiotics
   • Not routine for uncomplicated chronic discharge.
   • Consider when there is spreading infection, systemic illness, mastoiditis, cellulitis, or an intracranial/intratemporal complication.
   • A 2025 Cochrane review reassessed systemic antibiotics for CSOM, but treatment still needs to be individualized because evidence quality and applicability vary (PMID: 40484405).
4. Treat granulation tissue
   • Aural toilet and topical therapy first.
   • Persistent polyp requires specialist evaluation and sometimes biopsy.
5. Tympanoplasty / myringoplasty
   • Indications:
     • Persistent dry central perforation
     • Recurrent discharge despite appropriate medical treatment
     • Conductive hearing loss
     • Need to prevent water-related recurrent infection
   • May be combined with ossiculoplasty if ossicles are damaged.

C. Squamous COM / cholesteatoma

• Tympanomastoidectomy, with cholesteatoma removal
• Canal-wall-up or canal-wall-down mastoid surgery, depending on disease extent and anatomy
• Tympanoplasty and ossicular reconstruction when appropriate
• Long-term postoperative follow-up is essential because residual or recurrent disease can occur

D. Management of complications

• Urgent ENT referral or admission
• IV antibiotics where infection has spread
• CT temporal bone and MRI brain when indicated
• Prompt surgical drainage or mastoid surgery for mastoid, labyrinthine, facial nerve, or intracranial complications
• Neurosurgical input for intracranial abscess or venous sinus thrombosis

Exam summary

• Central perforation + mucopurulent discharge = mucosal/tubotympanic COM.
• Attic or marginal perforation, retraction pocket, keratin debris, foul-smelling discharge = suspect cholesteatoma.
• Investigate with otoscopy/microscopy, audiometry, culture when persistent, HRCT temporal bone for cholesteatoma or surgical planning.
• Treat uncomplicated active mucosal disease with aural toilet, topical non-ototoxic antibiotic drops, dry-ear precautions, then consider tympanoplasty.
• Treat cholesteatoma with definitive tympanomastoid surgery.