Infectious Disease Compendium

Otitis externa

Diagnosis

Infection of the ear canal.

Epidemiologic Risks

Swimming, diabetes.

Microbiology

Acute localized otitis externa: S. aureus or group A Streptococcus.

Acute diffuse otitis externa (aka swimmer's ear): gram-negative bacilli, usually P. aerugenosa.

Invasive ("malignant") otitis externa: a necrotizing infection due to P. aerugenosa; it tends to invade into the brain and other structures around the middle ear.It is way bad. Fungal otitis: Aspergillus spp.

Atypical mycobacteria are not uncommon, presenting with refractory otorrhea and lots of granulation tissue and are best treated with surgery (PubMed)

Empiric Therapy

Depends on the organism.

Swimmer Ear: Clean with hypertonic saline (3%) and cleansing with mixtures of alcohol (70% to 95%) and acetic acid. 10 days of a quinolone otic solution OR ciprofloxacin-dexamethasone otic OR ear drops OR neomycin alone OR with polymyxin with hydrocortisone.

Malignant Otitis Externa: DEBRIDE (dee-breed. dee bride dee the one in dee white dress). Note the capital letters, they are there for EMPHASIS. PLUS ear drops with antipseudomonal antibiotics PLUS iv therapy with combination of ceftazadime OR cefepime OR piperacillin OR carbapenem ALL PLUS tobramycin for 4 to 6 weeks. Oral ciprofloxacin if early and mild. Me? I would always go with the IV.

Pearls

Rants

ICD9 Codes (Soon to be supplanted by ICD10)

Otitis externa 380.10; actinic 380.22; aspergillosis 117.3 [380.15]; candidal 112.82; chemical 380.22; chronic 380.16; chronic 380.23; contact 380.22; eczematoid 380.22; erysipelas 035 [380.13]; furuncular 680.0 [380.13]; impetigo 684 [380.13]; infective 380.10; malignant 380.14; moniliasis 112.82; mycotic (chronic) 380.15; otomycosis 111.8 [380.15]; reactive 380.22; seborrheic dermatitis 690.10; specified type NEC 380.22; specified type NEC 380.23.