3.02 Otitis Externa (Swimmer's Ear)
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agk's Library of Common Simple Emergencies

Presentation
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The patient complains of ear pain, always 
uncomfortable and sometimes unbearable, often 
accompanied by drainage and a blocked 
sensation, sometimes by fever. When the 
condition is mild or chronic there may be 
itching rather than pain. Pulling on the 
auricle or pushing on the tragus of the ear 
classicly causes increased pain. The tissue 
lining the canal may be swollen. In severe 
cases the swelling can extend to soft tissue 
surrounding the ear. Tender erythematous 
swelling or an underlying furuncle may be 
present, and may be pointing or draining. The 
canal may be erythematous and dry or it may be 
covered with fuzzy cotton-like grayish or black 
fungal plaques. Most often, the canal lining is 
moist, covered with purulent drainage and 
debris, and cerumen is characteristically 
absent. The canal may be so swollen that it is 
difficult or impossible to view the tympanic 
membrane, which when seen often looks dull.

What to do:
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- Suction out the debris and drainage present 
   in the canal. Irrigation can be most 
   effective in cleaning out the canal. Inspect 
   for the presence of any foreign body.
- Incise and drain any furuncle that is 
   pointing or fluctuant.
- If the ear canal is too narrow for medication 
   to flow freely, insert a wick. Best is the 
   Pope ear wick (Merocel), about 1 by 10 mm of 
   compressed cellulose, which is thin enough 
   to slip into an occluded canal, but expands 
   when wet. If not available, try using 
   alligator forceps to insert quarter-inch 
   gauze (but this is more painful). After a 
   wick is inserted, water must be kept out of 
   the ear, and the patient must be instructed 
   to use soft wax ear plugs while showering.
- Prescribe a topical steroid solution for 
   instillation down the wick (Otic Tridesilon 
   Solution, Vosol HC, Acetasol HC, Cortico- 
   sporin Solution or Suspension), every six to 
   eight hours for the next 7-14 days. (Clear 
   solutions are usually used, because they do 
   not obscure follow up examination, but if 
   there might be a perforation of the tympanic 
   membrane, use a less-irritating suspension. 
   Ophthalmic gentamycin solution is a good 
   choice for pseudomonas. The antifungal 
   cresyl acetate solution (Cresylate) may be 
   used for a purely fungal infection.)
- With moderate to severe pain and soft tissue 
   swelling, or other signs of cellulitis, 
   prescribe an appropriate analgesic (e.g., 
   acetaminophen, ibuprofen, naproxen, hydro- 
   codone or oxycodone) and an antibiotic 
   (e.g., trimethaprim plus sulfamethoxyzole, 
   ciprofloxacin, dicloxicillin or cefadroxil) 
   and have the patient use warm, moist 
   compresses to help relieve any pain or 
   swelling.
- Provide follow up in one to two days for 
   removal of the wick and remaining debris 
   from the ear canal.
- Have the patient use a prophylactic 2% acetic 
   acid solution (e.g., Otic Domeboro Solution 
   or half-strength vinegar) after swimming or 
   bathing when the initial therapy has been 
   completed.

What not to do:
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- Do not use oral antibiotics for simple otitis 
   externa without evidence of cellulitis or 
   concurrent otitis media.
- Do not use topical antibiotics for prophy- 
   laxis. Long-term use of any topical anti- 
   biotics can lead to a fungal superinfection.
- Do not instill medication without first 
   cleansing the ear canal, unless restricted 
   because of pain.
- Do not expect medicine to enter a swollen- 
   shut canal without a wick.
- Do not use ear drops containing neomycin, 
   which sometimes causes allergic dermatitis.

Discussion
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Otitis externa has a seasonal occurrence, being 
more frequently encountered in the summer 
months, when the climate and contaminated water 
will most likely precipitate a fungal or 
Pseudomonas aeruginosa bacterial infection. 
Various dermatoses, diabetes, aggressive ear 
cleaning with cotton-tipped applicators, 
previous external ear infections and furuncul- 
osis also predispose patients to developing 
otitis externa.

The healthy ear canal is coated with cerumen 
and sloughed epithelium. Cerumen is water- 
repellant and acidic, and contains a number of 
antimicrobial substances. Repeated washing or 
cleaning can remove this defensive coating. 
Moisture retained in the ear canal is readily 
absorbed by the stratum corneum. The skin 
becomes macerated and edematous and the 
accumulation of debris may block gland ducts, 
preventing further production of the protective 
cerumen. Finally, endogenous or exogenous 
organisms invade the damaged canal epithelium 
and cause the infection.

Malignant or necrotizing external otitis is a 
life-threatening condition that occurs primar- 
ily in elderly diabetic patients as well as any 
immunocompromised individual. The pathognomonic 
sign of malignant external otitis is the 
presence of active granulation tissue in the 
ear canal. Early consultation should be obtain- 
ed if there is any suspicion of this condition 
in a susceptable patient with a draining ear.

The ear is innervated by the fifth, seventh, 
ninth and tenth cranial nerves and the second 
and third cervical nerves. Because of this rich 
nerve supply, the skin is extremely sensitive. 
Otalgia may arise directly from the seventh 
cranial nerve (geniculate ganglion), ninth 
cranial nerve (tympanic branch), the external 
ear, the mastoid air cells, the mouth, teeth, 
or esophagus. Ear pain can result from 
sinusitis, trigeminal neuralgia and temporo- 
mandibular joint dysfunction or be referred 
from disorders of the pharynx and larynx. A 
mild pain referred to the ear may be felt as 
itching, cause the patient to scratch the ear 
canal, and present as an external otitis. When 
the source of ear pain is not readily apparent, 
the patient should be referred for a more 
complete otolaryngologic investigation.

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