Otitis Externa & Media: Ear Infections Guide

Otitis externa infects the ear canal (swimmer's ear: trapped water invites infection). Otitis media infects the middle ear behind the eardrum, from sudden painful acute otitis media (AOM) in children to long-standing chronic suppurative otitis media (CSOM) with perforation and discharge. Together they are among the commonest reasons children see doctors.

Repeated ear discharge can silently damage hearing and delay speech and learning, while neglected chronic disease can spread to the brain. Knowing which part is infected, which germ is likely, and when a perforation is dangerous decides treatment.

Key Concepts

• Tragus tenderness: pain on pressing the tragus points to otitis externa; the deeper middle ear does not hurt on tragal pressure.
• Organisms: externa usually Pseudomonas aeruginosa or Aspergillus fungus (otomycosis); AOM usually S. pneumoniae, H. influenzae or M. catarrhalis via the Eustachian tube.
• Bulging tympanic membrane: in AOM the drum bulges, reddens and loses its light reflex; bulging distinguishes true AOM from a merely red drum in a cold.
• Glue ear: non-infected fluid behind an intact drum, muffling hearing without pain, common after colds.
• Safe vs unsafe CSOM: tubotympanic (central perforation, mucoid discharge) rarely complicates; atticoantral (attic perforation, foul discharge, cholesteatoma eroding bone) needs surgery.
• Malignant otitis externa: aggressive Pseudomonas skull-base infection in elderly diabetics with severe deep ear pain.

How It Works

Otitis externa starts when moisture or scratching damages canal skin; bacteria or fungus invade, causing itching, pain worse on chewing or tragal pressure, and a swollen discharging canal. Treatment is local: canal cleaning plus antibiotic-steroid drops, keeping the ear dry. Otitis media starts when a cold swells the Eustachian tube shut; absorbed air creates negative pressure sucking infected nasal secretions into the middle ear. AOM brings sudden severe pain, fever and a bulging drum; many cases resolve as the tube reopens, antibiotics reserved for severe or persistent ones. Lingering uninfected fluid becomes glue ear. Chronic perforated disease becomes CSOM: safe tubotympanic responds to dry-ear care and topical antibiotics, while unsafe atticoantral grows cholesteatoma toward the brain, needing mastoidectomy.

Worked Example

A 20 kg child needs amoxicillin 45 mg/kg/day in two doses for AOM:

1. Daily dose = 45 × 20 = 900 mg
2. Per dose = 900 ÷ 2 = 450 mg twice daily
3. With 250 mg/5 mL suspension: 450 ÷ 250 × 5 = 9 mL twice daily

Weight-based dosing works without excess side effects; the full course must finish even after pain settles.

Common Misconceptions

• "All ear discharge needs oral antibiotics." Externa usually heals with cleaning and topical drops; oral drugs are for severe swelling, fever or spread beyond the canal.
• "Every perforation needs surgery." Many heal with dry-ear care; surgery (myringoplasty/mastoidectomy) is for persistent unsafe disease with cholesteatoma.
• "Ear candling cleans safely." No proven benefit; it risks burns and deeper wax. Canals self-clean; only doctors should remove impaction.

Real-World Applications

• Pneumatic otoscopy: air puffs checking drum movement spot glue ear in seconds.
• Audiometry/tympanometry: quantify conductive hearing loss, guiding treatment timing.
• Vaccination: pneumococcal and Hib vaccines reduced AOM burden in immunized children.
• Mastoidectomy: removes cholesteatoma and infected bone, curing unsafe CSOM before brain complications.

Otitis externa is a canal infection with tragal tenderness, treated by cleaning plus topical drops; otitis media is middle-ear disease where a bulging drum means AOM, persistent fluid means glue ear, and chronic discharge splits into safe tubotympanic and unsafe cholesteatoma types. Weight-based amoxicillin treats AOM, vaccines prevent it, surgery rescues the unsafe ear.