Otitis externa Flashcards
What are the causes of otitis externa?
Infection: Bacterial (Staph aureus. Pseudomonas aeruginosa) Fungal
Seborrhoeic dermatitis
Contact dermatitis (allergic or iritant)
What is otits externa?
diffuse inflammation of the external ear canal which may also involve the pinna or tympanic membrane. involves the skin and subdermis
.
What are the presenting feature of otitis ext
Rapid onset:
ear pain
discharging ear
tenderness
itching
aural fullness
hearing loss (muffled from discahrge)
can be erythematous / swollen
What are risk factors for otitis externa?
external auditory canal obstruction
Environment: ++ humidity / ++ heat
swimming
local trauma
allergy
skin disease
Diabetes
immunocompromised
prolonged use of topical antibacterial agents
Examining a pt with otitis externa, what are the signs of ear canal inflammation?
Tenderness over :
Tragus
Pinna
What investigations for otitis externa?
Otoscopy
tympanometry (normal)
ear cultures (if failed to respond to therapy - will need AB)
CT scan of temporal bone with IV contrast (rule out Malignant OE - if pain disproportionate / granulation tissue on floor of ear canal, low threshold if diabetic / immunocompromised) - bony erosion and invasion of petrous bone
What is initial first line treatment for otitis externa?
Bacterial : topical antibiotic e.g. gentamicin / cirprofloxacin or a combined topical antibiotic with a steroid e.g. ciprofloxacin /hydrocortisone otic
Fungal: e.g. acetic acid
analgesia
don’t use aminoglycoside e.g gentamicin (ototoxic) if TM is perforated
Canal debris -remove
if canal is extensively swollen, ear wick is sometimes inserted
What do you need to do before the use of topical ear drops in otitis externa?
Clean the ear canal and remove debris
if very swollen and oedeamtous may need ear wick
Which groups of pts are not suitable for 1st line topical antibacterial ear drops + analgesia?
Diabetes, HIV/AIDs, immunocompromised, Hx of radiotherapy, signs of fungal infection, signs of malignant otitis externa
What is the point of an ear wick in management of otitis externa?
Allows for drug delivery in the ear as severe swelling of ear can make applying ear drops difficult
What are some differentials for otitis externa ?
Acute otitis media
Furunculosis
contact dermatitis of ear canal
viral infection of external ear
chronic otitis externa
cancer of external auditory canal
cholesteatoma
What are some complications of otitis externa ?
contact dermatitis - hypersensitivity rxn to medication e.g. neomycin
What do NICE guidlelines say you need to made a diagnosis of acute otitis externa?
Rapid onset (generally within 48 hours) of symptoms within the past 3 weeks, coupled with signs of ear canal inflammation.
What is malignant otitis externa? Who gets it?
Diabetic / immunocompromised pts
an aggressive infection where infection spreads from soft tissue of ear canal to bone - hight mortality rate
Presentation of malignant otitis externa ?
chronic ear discharge despite topical treatment
sever ear pain
sometimes cranial nerve palsy (CNVII)
granulation tissue in ear canal
