Chronic Suppurative Otitis Media

Condition

Infection of the middle ear with a perforated eardrum and discharge for at least 6 weeks. Can cause hearing impairment and disability. CSOM has two distinct types: the tubotympanic (benign) type, a permanent central perforation not generally prone to severe complications, and the atticoantral (malignant/“danger”) type, involving the attic and posterosuperior middle ear, which carries a much higher risk of serious complications.

CSOM is usually polymicrobial — commonly Pseudomonas aeruginosa, Staphylococcus aureus, Proteus species and anaerobes — and these organisms often form biofilms on the middle ear mucosa, which increases resistance to host immune defences and reduces antibiotic effectiveness. It typically follows untreated, inadequately treated, or recurrent acute otitis media that leaves a persistent perforation; risk is also increased by eustachian tube dysfunction, cholesteatoma, immunocompromise, and craniofacial abnormalities such as Down syndrome, cleft palate/cleft lip, and 22q11.2 deletion (velocardiofacial/DiGeorge) syndrome. Globally, CSOM is estimated to affect around 1 in 26 people (over 297 million, including 64 million with bilateral disease), with prevalence around 1–3% in high-income countries and up to 4% in resource-limited settings, and it is a leading cause of preventable hearing loss worldwide — hearing loss correlates with both perforation size and disease chronicity. Occasionally — especially in developing countries and Aboriginal or Torres Strait Islander people — serious complications can occur, such as intracranial infection and acute mastoiditis. Other complications include facial nerve paralysis, and rarer but serious intracranial extension (meningitis, brain abscess, sigmoid sinus thrombosis).

Pain is uncommon in uncomplicated CSOM unless an associated osteitis is present — significant otalgia, vertigo, or facial weakness should prompt assessment for a complication rather than being treated as routine CSOM.

Diagnosis

CSOM is a clinical diagnosis based on history and otoscopy; further testing is reserved for selected cases rather than done routinely. Aural discharge culture is recommended for refractory, recurrent, or complicated disease, or when empiric topical treatment fails. High-resolution CT of the temporal bone is preferred for evaluating complications or planning surgery (mastoid disease, ossicular erosion, cholesteatoma), while MRI — with diffusion-weighted imaging — is used when intracranial extension or cholesteatoma is suspected, as it helps distinguish cholesteatoma from granulation tissue. Pure-tone audiometry and tympanometry (typically a flat Type B trace) support the diagnosis and quantify the (usually conductive) hearing loss.

Management

Cleaning the external ear canal by dry aural toilet is important and should be performed before instilling ear drops (as for otitis externa).

Topical antibiotics alone: ciprofloxacin 0.3% ear drops, 5 drops twice daily, until free of discharge for at least 3 days. Quinolone drops (ciprofloxacin, ofloxacin) are preferred because, unlike aminoglycosides, they are not ototoxic even with a perforated eardrum; ear-drop preparations containing aminoglycosides (e.g. neomycin, tobramycin) or polymyxin should not be used with a perforated tympanic membrane or a tympanostomy tube because of the risk of ototoxicity. The equivalent US guidance (MSD Manual) gives a fixed 14-day course of ciprofloxacin or ofloxacin rather than a symptom-driven endpoint — a difference in regimen framing, not a contradiction of the eTG-based duration above.

There’s inadequate evidence to support adding topical corticosteroids to topical antibiotics. An updated 2025 Cochrane review of 19 studies found no evidence that adding a steroid changes resolution of discharge at one to two weeks, and low-certainty evidence that a topical antibiotic alone may in fact do better than an antibiotic-steroid combination for some antibiotic classes. When granulation tissue is present it can be controlled with topical antimicrobial drops, topical corticosteroids, or — if needed — chemical cautery with silver nitrate. Systemic antibiotics are reserved for cases with systemic infection, complications, or failure of topical treatment.

Refer to an otolaryngologist for further examination and to exclude cholesteatoma or chronic osteitis. Surgery (tympanoplasty ± mastoidectomy) is indicated for otorrhea persisting 4–6 weeks despite medical management, a non-healing perforation, cholesteatoma, conductive hearing loss, or coalescent mastoiditis.

High-risk population management (per the ATSI otitis media clinical care guidelines): dry-mopping followed by ciprofloxacin 2–5 drops 2–4 times daily, continued until the ear is dry for at least 3 days (may require prolonged treatment) — review weekly. If persistent CSOM after 4 months of treatment, consider hospital admission for IV/IM ceftazidime. A dry perforation with normal hearing needs only regular review; mild hearing loss (20–35dB) warrants communication-support strategies and consideration of ENT referral; hearing loss >35dB warrants referral for mastoidectomy/tympanoplasty and hearing aids if needed.

Prognosis

Prognosis is generally favourable with treatment — topical fluoroquinolone antibiotics plus regular aural toilet resolve otorrhea in most patients — but recurrence is common and a persistent perforation predisposes to further infection and ongoing hearing impairment. Early recognition and treatment, before advanced middle-ear or intracranial complications develop, is the main determinant of long-term outcome.