Symptoms and Signs of Otitis Externa
The diagnosis of acute otitis externa requires rapid onset (within 48 hours) of at least one characteristic symptom combined with two clinical signs: symptoms include otalgia, otorrhea, and itching, while signs include tragal/pinna tenderness, ear canal edema, ear canal erythema, and wet debris. 1
Cardinal Symptom: Otalgia
- Ear pain (otalgia) is the hallmark symptom, often severe and disproportionate to visual findings on examination 1
- Pain may be accompanied by itching or a sensation of fullness in the ear 1
- Jaw pain can occur as a referred symptom 1
Pathognomonic Sign: Tragal Tenderness
- Tenderness of the tragus, pinna, or both is the hallmark physical finding and distinguishes otitis externa from otitis media 1
- This tenderness is often intense and helps differentiate external from middle ear pathology 1
- Pain with manipulation of the tragus or pinna is characteristic 2
Visual Examination Findings
- Diffuse ear canal edema and erythema are key signs on otoscopy 1, 2
- Wet debris or otorrhea may be present in the canal 1
- The tympanic membrane may show erythema, which can mimic acute otitis media 1
Critical Differentiating Feature
- Normal tympanic membrane mobility on pneumatic otoscopy distinguishes otitis externa from otitis media with effusion 1, 2
- Pneumatic otoscopy demonstrates good mobility in otitis externa but absent or limited mobility in acute otitis media 1
- Tympanometry shows a normal peaked curve with otitis externa versus a flat tracing with otitis media 1
Additional Clinical Features
- Fever may be present but is not required for diagnosis 1
- Regional lymphadenitis can occur 1
- Cellulitis of the pinna and adjacent skin may develop in more advanced cases 1
- Hearing loss (typically conductive) may occur if canal edema is severe 1
Diagnostic Criteria Summary
The American Academy of Otolaryngology-Head and Neck Surgery specifies that diagnosis requires: 1
- Rapid onset (generally within 48 hours) in the past 3 weeks
- At least 1 characteristic symptom: otalgia, otorrhea, or itchiness
- At least 2 signs: tragal tenderness, ear canal edema, ear canal erythema, or wet debris
- Microbiological identification is not required for diagnosis 1
Common Pitfall to Avoid
Do not confuse otitis externa with acute otitis media based solely on tympanic membrane erythema—always perform pneumatic otoscopy to assess membrane mobility, which remains normal in otitis externa 1. The presence of tragal tenderness strongly favors otitis externa over middle ear pathology 1.