Otitis externa Flashcards
What is otitis externa?
inflammation of the skin in the external ear canal
Give 5 causes of otitis externa:
1) bacterial infection
2) fungal infection
3) eczema
4) seborrheic dermatitis
5) contact dermatitis
Give the fungi known to cause otitis externa:
1) candida
2) aspergillus
Why is topical antibiotic use a risk factor for fungal otitis media?
the topic antibiotics can kill ‘friendly’ flora which have a protective effect fungal infections
What are the two most common bacterial causes of otitis externa?
1) Pseudomonas aeruginosa
2) Staphylococcus aureus
Is Pseudomonas aeruginosa gram positive or gram negative?
gram negative
Give 8 presentations associated with otitis externa:
1) ear pain
2) discharge
3) itchiness
4) conductive hearing loss (if the ear gets blocked)
5) erythema and swelling in the ear canal
6) tenderness of the ear canal
7) pus or discharge in the ear canal
8) lymphadenopathy in the neck or around the ears
What is the gold standard diagnostic tool for otitis externa?
otoscopy
What investigation can be carried out to identify the causative organism in otitis externa?
ear swab
What is the treatment for mild otitis externa?
acetic acid 2% (EarCalm)
What is the treatment strategy for moderate otitis externa?
topical antibiotics and steroid spray/drops
Give 4 combinations of topical antibiotic and steroid used to treat moderate otitis externa:
1) Neomycin and dexamethasone
2) Neomycin and betamethasone
3) Gentamicin and hydrocortisone
4) Ciprofloxacin and dexamethasone
True or false: aminoglycosides are otoxic
true
Give two examples of aminoglycosides:
1) gentamicin
2) neomycin
What essential precaution must be made when prescribing topical aminoglycosides in the ear (and why)?
a perforated tympanic membrane must be excluded as aminoglycosides can cause hearing loss if it passes the tympanic membrane
What is the treatment strategy for severe otitis externa?
oral flucloxacillin or clarithromycin
What topical medication is used to treat fungal otitis externa?
clotrimazole
What is malignant otitis externa?
a severe form of otitis externa that spreads to the temporal bone and can progress to osteomyelitis
In which patients is malignant otitis externa most commonly seen?
immunocompromised (diabetics, HIV, chemotherapy)
Give 4 presentations associated with malignant otitis externa:
1) severe otitis externa symptoms
2) persistent headache
3) fever
4) granulation tissue at the junction between the bone and cartilage of the ear
What is the characteristic examination finding associated with malignant otitis externa?
granulation tissue at the junction between the bone and cartilage of the ear
What is the treatment strategy for malignant otitis externa?
1) admit to hospital
2) IV antibiotics
3) CT/ MRI head
Give 4 complications of malignant otitis externa:
1) cranial nerve damage
2) meningitis
3) intracranial thrombosis
4) death
