Acute otitis externa Flashcards
What is acute otitis externa?
- Infective condition w/ inflammation of the skin of the EAC
- Generalised inflammation of EAC (vs localised in furuncle)
What are the risk factors for acquiring acute otitis externa?
Systemic
- Skin conditions (e.g. eczema, psoriasis)
- Skin infections (e.g. impetigo)
- Immunocompromised e.g. diabetes
Local
- Trauma (cotton-bud, dirty fingernail)
- Local infection (viral/bacterial/fungal)
- 2° to middle ear suppuration
- Irritation due to constant exposure to water (‘Swimmer’s ear’)
What are the pathogens that cause acute otitis externa?
- Bacterial: Pseudomonas (very common), Staph (very common), Strep
- Fungal (otomycosis): Candida albicans (white spores), Aspergillus niger (black spores)
- Viral
What are the symptoms of acute otitis externa?
Pain, itch, discharge, +/- CHL (inflam and debris partially/totally occluding EAC)
What are the complications of AOE?
Perichondritis (spread to the auricle) -> can result in avascular necrosis (AVN) -> deformity (cauliflower ear)
Facial cellulitis (spread to surrounding tissues)
When pinna inflammation doesn’t affect earlobe 🡪 only cartilage is affected (i.e. perichondritis). If earlobe is involved 🡪 skin is affected (not just cartilage) (i.e. cellulitis). This distinction arises because the earlobe is devoid of cartilage.
Malignant otitis externa (MOE) (in elderly, DM, immunocompromised)
What is the management of AOE?
Treatment
- **Regular aural toilet via suction or dry mopping: most impt in reducing pathogen load.
- Bac: Topical Sofradex +/- systemic abx for gross cellulitis, perichondritis, or MOE. KIV oral abx if there is spread (perichondritis, cellulitis) or osteomyelitis (malignant otitis externa MOE)
- Fungal: Topical clotrimazole (Canestan), warn of burning sensation during application
- Adequate analgesia if patient complaints of pain
Prevention – pt education
- KED (keep ears dry) – block ears w cotton balls coated in - Vaseline, avoid all water based activities. Ear plugs not preferred as harder to keep clean
- Do not put object
TCU clinic: after inflam settles, examine TM to exclude middle ear disease as underlying cause
Often self-limiting, but watch closely for elderly, diabetics and immunocompromised for possible development into malignant otitis externa MOE
What is a furuncle?
- localised otitis externa
- Infection of hair follicle 2’ obstruction of sebaceous duct (only outer 1/3 of EAC is hair-bearing & cartilaginous)
- Usually occurs when patient digs ear with nails and breaks the skin
What is the pathogen that cause a furuncle?
Staph. aureus
What are the clinical features of a furuncle?
otalgia, CHL (if obstructing EAC)
How is a furuncle managed?
- Topical abx +/- oral (systemic) abx
- KIV drainage + packing the EAC to prevent pus collection
What are the risk factors of Malignant otitis externa (MOE)?
elderly, diabetic, immunocompromised
What is the pathogen that causes MOE?
Pseudomonas (95%) 🡪 spreads to bone, producing osteomyelitis of skull base
What are the symptoms of MOE?
- Severe otalgia (nocturnal, extending into the TMJ -> pain w chewing)
- Otorrhoea (unresponsive to routine topicals for otitis externa)
Otalgia and otorrhoea in an elderly diabetic pt = malignant otitis externa (MOE) until proven otherwis
What are the signs of MOE?
- Granulation tissue at inferior portion of EAC (bone-cartilage junction)
- CN palsies: CN 7 and nerves exiting jugular foramen (CN 9, 10, 11)
What is the complications of MOE?
- Meningitis
- Brain abscess
- Sigmoid sinus thrombophlebitis
