1. Otitis Externa

2. Definition Otitis externa (OE) also known as “swimmer’s ear”
either an inflammation or infection of the external auditory canal (EAC) or the auricle or sometimes both.
Usually due to bacterial infection of the skin of the ear canal
Common bacterial pathogen include
Pseudomonas aeruginosa 
Enterobacteriaceae
Staphylococcus aureus

3. Epidemiology Found in all regions of the US
4 in every 1000 people annually
Affects both sexes equally
Infection is most prevalent in older pediatric and young adult patients (peak incidence in children age 7-12) and those 65 and older

4. Signs and Symptoms
The key physical finding of OE is pain with movement of the tragus or the pinna (the hallmark of OE).
Other signs and symptoms include:
Otalgia
Pruritus
Ear fullness or pressure
Narrowing of the external auditory canal
Tinnitus
Fever
Discharge

5. Common History Findings
History of exposure to or activities in water
History of recent ear trauma (forceful ear cleaning, cleaning ear with cotton swabs)

6. Classification Acute diffuse OE Acute localized OE Chronic OE
Eczematous (eczematoid) OE
Necrotizing (malignant) OE 
Otomycosis

7. Acute Localized Otitis Externa
This condition, also known as furunculosis, is associated with infection of a hair follicle

8. Acute Diffuse Otitis Externa
Otoscopic Appearance:
Canal edema with erythema and exudate
This is the most common form of OE, typically seen in swimmers; it is characterized by rapid onset (generally within 48 hours) and symptoms of EAC inflammation as well as tenderness of the tragus or pinna or diffuse ear edema or erythema or both, with or without otorrhea, regional lymphadenitis, tympanic membrane erythema, or cellulitis of the pinna L3

9. Chronic Otitis Externa
Otoscopic appearance:
Skin of the external canal is shiny
Skin may be erythematous
Normal cerumen is usually absent
Skin lining the deep canal may show
marked hyperemia and is often covered in white patchy and purulent exudate.
This is the same as acute diffuse OE but is of longer duration (>6 weeks)

10. Necrotizing (malignant) Otitis Externa
Otoscopic appearance:
Key finding is an area of infected granulation tissue on the floor of the cartilaginous ear canal near the junction between the cartilaginous and bony portions of the canal.
Meatus filled with purulent discharge
Infection that extends into the deeper tissues adjacent to the EAC
Primarily occurs in adult patients who are immunocompromised (rarely in children)
It may result in cases of cellulitis and osteomyelitis

11. Otomycosis
Infection of the ear canal secondary to fungus species such as Candida or Aspergillus
Otomycosis caused by Aspergillus. Note the
characteristic gray-black fungal elements on the debris.
Otomycosis caused by Candida. Note the
characteristic white fungal elements on the debris.

12. Otomycosis
Otoscopy Appearance: Examination of right external auditory canal shows slightly edematous and erythematous canal leading to impacted debris. Note the yellow purulence surrounding the white mycelium of the fungal infection with a few black conidiophores (fruiting body of fungus) intermixed. Red arrow denotes superior orientation. R2

13. Eczematous (eczematoid) Otitis Externa
Various dermatologic conditions that may infect the EAC and cause OE

14. Diagnosis General Clinical Diagnosis (Otoscopy examination)
necrotizing OE needs to be ruled out by an otolaryngologist if patients is diabetic or immunocompromised and presents with severe pain in the ear.

15. Diagnosis Lab testing
Usually only indicated if the patient is immunocompromised, if symptoms are refractory to treatments, or if a fungal etiology is suspected.
Tests may include the following:
1) Gram Stain
2) Blood glucose level
3) Urine dipstick

16. Diagnosis Imaging
Indication for imaging if suspecting either necrotizing OE or mastoiditis.
Imaging modalities
1) CT (preferred for better resolution of bone erosion)
2) Radionucleotid bone scanning
3) Gallium scanning
4) MRI (used if soft tissue extension is the primary concern)

17. Treatment Primary treatment of otitis externa 1) management of pain
2) Cleaning the EAC
3) Topical antibiotics and steroids
4) IV antibiotics may be needed for individuals at risk for
necrotizing OE
Most cases can be treated with OTC analgesics and topical eardrops
Surgical debridement is rarely indicated
Necrotizing OE is not a surgical disease !