Otitis Externa

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

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

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

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

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

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

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

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)

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

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.

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

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

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.

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

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)

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 !