Australian Doctor Australian Doctor 30th June 2017

and can involve the ear canal and surrounding tissue, mimicking otitis externa. 9, 10 These conditions not only mimic otitis externa but can predispose individuals to frequent infections of the ear canal.

Patients with eczema present with chronic itch affecting multiple sites, typically starting in childhood. They often have a history of other atopic conditions such as hayfever or asthma, and may also have a family history of atopy. Management can be guided by dermatologists but generally consists of application of emollients, careful prevention of excess moisture and the use of topical corticosteroids such as mometasone.

Seborrhoeic dermatitis is a common condition affecting the eyebrows, scalp and facial hair as well as the external auditory canal. This typically presents as greasy yellowish scaling, itching, and secondary inflammation. Seborrhoeic dermatitis is caused by malassezia yeast species and is more common in people with diabetes or HIV infection, and those with Down syndrome and Parkinson’ s disease. 13 Treatment includes the use of topical antifungal medications such as clotrimazole to eradicate the yeast, and topical steroids such as mometasone for symptom relief.

Systemic and discoid lupus erythematosus, which often have other systemic manifestations of disease, may also mimic otitis externa. These disorders are best managed with advice from dermatologists.

Exostoses and osteomas Bony outgrowths of the external auditory canal may be noticed on otoscopy( see figure 7). These can either be osteomas, which are often pedunculated, solitary, unilateral lesions; or they can be exostoses, which are multiple, bilateral, broad-based lesions associated with cold water exposure.

Exostoses occur in 70-80 % of surfers and the degree of obstruction increases with the frequency and duration of surfing. 14 Mild to moderate obstruction often causes water trapping, which is either avoided with ear plugs or treated with alcohol-based drops which evaporate the water.

These lesions can result in frequent bouts of otitis externa and when the canal obstruction becomes severe, conductive hearing loss develops. Referral to a specialist for review and consideration of surgery is suggested if there are symptoms such as recurrent infections, frequent water trapping or conductive hearing loss associated with the presence of large exostoses.

Case study

TONY, aged 22, presents to his GP complaining of left sided otorrhoea, itch, otalgia and jaw pain. He has recently returned from a trip to Bali where he had been swimming a lot. He was otherwise well with no previous otological problems and no past medical or surgical history.

On examination, Tony has mild pain on manipulation of his pinna.

Cerumen Cerumen is a mixture of sebum and modified secretions from modified apocrine sweat glands and shed skin cells. It is produced in the outer third of the ear canal and naturally migrates out of the canal, mixing with hair and other debris in the canal. Cerumen impaction is defined as a build-up of cerumen in the ear canal, resulting in symptoms or preventing a needed assessment of the ear canal or tympanic membrane. Cerumen impaction occurs in 5 % of adults, 10 % of children and almost a third of older or developmentally delayed patients. 15

The symptoms associated with cerumen impaction include conductive hearing loss, tinnitus, itch, pain, fullness, or malodorous discharge. If patients do not complain of symptoms and there is no need to assess the auditory system, excess cerumen does not require clearing and a watchful waiting approach can be taken. The application of a mineral oil can be used weekly to reduce wax accumulation by assisting in the natural movement of wax from the tympanic membrane to the lateral meatus.

Cerumen removal is recommended in patients who have symptoms of impacted cerumen or cerumen preventing assessment of the auditory system. 16

Various options are available for the removal of cerumen. Irrigation with sterile warm water involves flushing wax out with gentle jets of fluid. Manual removal of cerumen from the external auditory canal can be performed using a

HE HAS RECENTLY RETURNED FROM A TRIP TO BALI WHERE HE HAD BEEN SWIMMING A LOT.

There is associated mild erythema and swelling of the external auditory canal with a visibly normal tympanic membrane. The swelling does not extend to the pinna or surrounding skin and there is no cervical lymphadenopathy.

The GP diagnoses otitis externa, starts Tony on oral cephalexin and advises him to come back in one week, or sooner, if symptoms

Figure 8. Dry cerumen seen in an external auditory canal.

combination of microscopic suction, curettes, forceps, hooks or probes. This should only be performed by practitioners trained in this method who have access to directly visualise the instruments while clearing the wax. Cerumenolytics( wax-softening agents) can be used alone or with either irrigation or manual removal to remove wax. Cerumenolytics have been proven to improve the clearance of cerumen when used daily for five days or when used immediately prior to irrigation. Two applications of the agent every 15 minutes prior to irrigation has been found to be superior to application in the days leading up to irrigation. 16

There is no evidence to suggest one type of cerumenolytic is better than another. There are various commercially available options— accessibility, cost and patient preference should determine which agent the patient chooses.

Irrigation involves using warmed water and either a syringe or electronic irrigator. Less water is required if the cerumen is pretreated with water 15 minutes prior to irrigation. The main complications of irrigation are pain, injury to the skin of the ear canal with resultant otitis externa, disequilibrium, hearing loss and tympanic membrane perforations.

Irrigation is contraindicated in patients who have had prior ear surgery, active otitis externa, underlying dermatological conditions affecting the external ear or a non-intact tympanic membrane. Irrigation should be used with caution in those with recurrent otitis externa, diabetes or other immunocompromised

states as it can lead to the development of skull base osteomyelitis. 17

Manual removal of cerumen can be faster than irrigation, allows for direct visualisation and does not moisten the ear canal. Manual removal relies on a combination of technical expertise and adequate lighting, visualisation down a narrow canal and specialised instrumentation. Instruments used for this include a microscope or specialised magnifying-illuminating goggles, a wax curette, a suction device with suction catheter or microscopic forceps. Manual removal requires a co-operative patient as it can be painful and result in trauma to the structures of the external ear or even tympanic membrane if the patient moves unexpectedly.

There have been reports of infections following manual removal but there is no evidence to suggest it is a risk factor for otitis externa. 18 Manual removal is recommended in certain scenarios( see box 5) where irrigation is contraindicated.

Provide patients with lifestyle advice to avoid the re-accumulation of impacted cerumen. This includes avoidance of inserting foreign objects such as cotton tips into the ear canal. This merely pushes cerumen further into the medial canal and contributes to impaction. In patients with hearing aids, this advice is impossible to follow so care must be taken to carefully clean aids and see a clinician should their hearing reduce. The regular use of cerumenolytics can also prove effective in certain patients.

do not subside. Tony’ s symptoms worsen over the course of the next few days and he returns to his GP, who sends him to the ED. On examination, Tony now has inflammation of the pinna and preauricular swelling( see figure) with tender cervical lymphadenopathy. His tympanic membrane is no longer visible because of the canal cont’ d next page

References

1. Prasad HKC, et al. Perichondritis of the auricle and its management. Journal of Laryngology & Otology 2007; 121( 6): 530-34.

2. Sand M, et al. Cutaneous lesions of the external ear. Head & Face Medicine 2008; 4:2.

3. Wang RY, et al. Syndromic ear anomalies and renal ultrasounds. Pediatrics 2001; 108( 2): E32.

4. McKean SA, Hussain SSM. Otitis externa. Clinical Otolaryngology 2007; 32:457-59.

5. Cheffins T, et al. Acute otitis externa: Management by GPs in North Queensland. Australian Family Physician 2009; 38( 4).

6. Rowlands S, et al. Otitis externa in UK general practice: a survey using the UK General Practice Research Database. British Journal of General Practice 2001; 51:533-38.

7. Wipperman J. Otitis externa. Primary Care 2014; 41:1-9.

8. Roland PS, Stroman DW. Microbiology of acute otitis externa. Laryngoscope 2002; 112( 7 Pt 1): 1166-77.

9. Brant J, Ruckenstein M. Infections of the External Ear. In: Flint, P, et al( editors). Cumming’ s Otolaryngology. 5th edn. Mosby Elsevier, Philadelphia, 2015.

10. Rosenfeld RM, et al. Clinical practice guideline: Acute otitis externa. Otolaryngology— Head and Neck Surgery 2014; 150( 1 Suppl): S1-s24.

11. Kaushik V, et al. Interventions to treat acute otitis externa, a specific form of ear canal inflammation also known as swimmer’ s ear. Cochrane Database of Systematic Reviews 2010( 1): Cd004740.

12. Hollis S, Evans K. Management of malignant( necrotising) otitis externa. Journal of Laryngology & Otology 2011; 125:1212-17.

13. Lambert PR, et al. Seborrheic keratosis of the ear canal. Otolaryngology— Head and Neck Surgery 1987; 96:198-201.

14. Wong BJ, et al. Prevalence of external auditory canal exostoses in surfers. Archives of Otolaryngology— Head and Neck Surgery 1999; 125:969-72.

15. Roeser RJ, Ballachanda BB. Physiology, pathophysiology, and anthropology / epidemiology of human earcanal secretions. Journal of the American Academy of Audiology 1997; 8:391-400. 16. Roland PS, et al. Clinical practice guideline: cerumen impaction. Otolaryngology— Head and Neck Surgery 2008; 139( 3 Suppl 2): S1- s21.

17. Grossan M. Cerumen removal— current challenges. Ear, Nose, & Throat Journal 1998; 77:541-6, 548.

18. Guidi JL, et al. Risk of otitis externa following manual cerumen removal. Annals of Otology, Rhinology & Laryngology 2014; 123:482-84.

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Case study