Otorrhoea and otitis externa Flashcards
How do you assess a discharging ear?
If anybody presents with a discharging ear the following are important points to gain from the history:
- Duration?
- Is there associated pain (otalgia)?
- Is there any discharge (otorrhoea) and is this thick, watery, offensive?
- Is there any associated hearing loss (and how does this affect the patient)?
- Are there any problems with balance?
- Is there any tinnitus?
- What treatment have they had so far and has it responded?
- What hobbies or sports are they involved in and do they get water in the ear e.g. swimming
- Have they had any surgery to the affected ear?
- Do they have any other significant medical problems e.g. allergic chronic rhinosinusitis, asthma, diabetes?
- Systemic disease (e.g., stroke, multiple sclerosis, cardiovascular disease).
- Ototoxic drugs (antibiotics (e.g., gentamicin), diuretics, cytotoxic).
- Exposure to noise (e.g., pneumatic drill or shooting).
- History of atopy and allergy in children.
What is otitis externa?
This is the inflammation of the outer ear.
Includes all the inflammatory conditions of the auricle, external auditory canal and outer surface of the eardrum.
Can be localised or diffuse and may be acute or chronic.
What are the risk factors for otitis externa?
Hot and humid climates.
Swimming.
Older age.
Immunocompromise (e.g. HIV)
DM
Narrow external auditory meatus
Obstruction of normal meatus such as keratosis obturans, foreign body, hearing aid, hirsute ear canal.
Insufficient ear wax
Wax build-up- lead to obstruction, retention of water and debris, and infection.
Eczema and seborrheic dermatitis
Allergic, atopic or irritant dermatitis
Trauma to ear canal from cotton buds and radiotherapy.
Microbiologica from active otitis media, exposure to pseudomonas aeruginosa or fungi.
Previous tympanostomy
Radiotherapy to ear
What is the cause of otitis externa?
Otitis externa results from a disturbance of the lipid/acid balance of the ear canal.
It is most usually infectious but may be caused by allergies, irritants or inflammatory conditions (all of which may also underlie bacterial infection).
Infection of the outer ear is usually bacterial (90%) or fungal (10%). Most cases involve multiple organisms, with the majority involving Staphylococcus aureus and/or P. aeruginosa.
Fungal infection usually follows prolonged treatment with antibiotics, with or without steroids. 90% of fungal infections involve Aspergillus spp. and the rest are Candida spp. Dermatophyte infection may occur and seborrhoeic dermatitis may be followed by infection with Malassezia spp.
Herpes zoster (Ramsay Hunt syndrome).
Infection may be localised to an infected hair follicle, causing a furuncle or localised otitis externa (S. aureus is the usual infecting organism).
Causes include acne, psoriasis, atopic eczema, SLE and seborrheic dermatitis.
What are irritants that can cause otitis externa?
Topical medications, hearing aids or earplugs.
Aggravating factors such as ear trauma from foreign bodies in the ear, cotton buds, ear syringing or hearing aids.
Water in the ear in swimmers, especially in polluted water.
Chemicals including hair spray, hair dyes and cerumenolytics.
What is the presentation of otitis externa?
The main symptoms are pain and itching. There may also be discharge and hearing loss. Findings on otoscopy are:
- Ear canal with erythema, oedema and exudate.
- Mobile tympanic membrane.
- Pain with movement of the tragus or auricle.
- Pre-auricular lymphadenopathy.
The condition is generally more severe with any of the following:
- Oedematous ear canal narrowed and obscured by debris.
- Hearing loss.
- Discharge.
- Regional lymphadenopathy.
- Cellulitis spreading beyond the ear.
- Fever.
What are the different types of otitis externa?
Acute diffuse OE Chronic OE Superficial fungal infection Furuncle Contact dermatitis Necrotising OE
What is the presentation of acute diffuse OE?
Presentation of otitis externa
Hearing may be impaired
Bacterial infection is common
Slight thick discharge, which can become bloody later.
Water creates a perfect medium for bacterial growth.
What is chronic OE?
OE lasting more than 12 weeks.
If due to infection, it is usually fungal.
Underlying skin conditions, diabetes, immunosuppression or prolonged use of antibiotic ear drops may contribute.
Symptoms are as for acute diffuse otitis externa. Discharge and itch are common.
What is a furuncle?
Small localised infection with severe pain in the ear and local swelling of the canal.
Pyrexia is moderate (less than 38°C).
There may be posterior auricular lymphadenopathy.
Auriscope examination can be very painful.
If the lesion bursts there is sudden relief of pain.
What is necrotising OE?
A life-threatening extension of otitis externa into the mastoid and temporal bones.
Usually due to P. aeruginosa or S. aureus.
Usually affects elderly patients with diabetes or patients who are immunocompromised.
Pain and headache of greater intensity than clinical signs would suggest.
Facial nerve palsy is a red flag sign but is not necessarily associated with a poorer prognosis.
What is the criteria for diagnosing necrotising OE?
Pain.
Oedema.
Exudate.
Granulation tissue (may be present at the junction of bone and cartilage).
Microabscess (when operated upon).
Positive bone scan or failure of local treatment.
Pseudomonas spp. in culture.
A technetium bone scan is needed to exclude osteomyelitis.
Computed tomography may be useful in predicting the extent of skull involvement
What are the investigations for OE?
Swabs recommended if there has been treatment failure.
Swabs best taken from the medial aspect of the ear canal under visualisation to reduce contamination.
Assess integrity of tympanic membrane, perforation may be assumed if the person:
- Can taste medication placed in the ear; or
- Can blow air out of the ear when the nose is pinched; or
- Has a tympanostomy tube in situ.
What are the differentials of OE?
Foreign bodies may be present. Impacted wax can cause pain and deafness. Otitis media Chronic suppurative otitis media Cholesteatoma.
What is the management of acute OE?
Managed with topical drops.
- BNF recommends neomycin or clioquinol (which also covers fungal infections). usually for 6 days.
- Aminoglycosides are relatively contra-indicated if there is perforation of the eardrum, as they can be ototoxic: they are used cautiously as second-line. They can cause contact dermatitis, although rarely after a short course.
- Recommended steroids are betamethasone, hydrocortisone, prednisolone, dexamethasone and flumetasone.
Wicking and removal of debris may be helpful.
-If there is extensive swelling of the auditory canal, consider inserting an ear wick (may require ENT referral). It should be impregnated with antibiotic-steroid combination and is inserted into the auditory canal.
Patients with systemic symptoms need same-day ENT review and may need admission for IV antibiotics.
