Creepy, Crawly Foreign Bodies in the Ear

The Pre-brief

Yes, the headlines are true. No, this isn’t about covid, but another bug – a cockroach – found in a man’s ear. A 40-year-old male went swimming in New Zealand and left with an insect friend – a cockroach, who had burrowed inside his ear and stayed there for three days! The rest of the horrifying story can be found here https://www.cnn.com/2022/01/13/asia/cockroach-ear-new-zealand-scli-intl/index.html. While this patient was invaded while he was swimming, this also occurs while patients are sleeping. 

These patients may present to the emergency department (ED) with the chief complaint often being severe ear pain. When inspecting the patient’s ear, the healthcare practitioner may notice a bug, most often a cockroach, waving back hello. Similar news stories seem to pop up from time to time which begs the question, how should these patients be managed? 

Foreign Bodies in the Ear

Patients presenting with an external auditory canal foreign body is a relatively common problem with an incidence ranging from 1 in 219 patient encounters to 1 in 1792 emergency department registrations according to previous studies. Foreign bodies of the insect variety in the external auditory canal may cause patients great distress as a result of otalgia and tinnitus. In a retrospective chart review by Antonelli et. al., insect aural foreign bodies were common, comprising approximately 14% of all foreign bodies found. Cockroaches were the most commonly identified insect (78%). Another study by Thompson and colleagues of 162 patients presenting to the ED with an external auditory canal foreign body identified 18% of cases were insects. In a review of 98 cases by Bressler and Shelton of patients presenting to the Otolaryngology service, cockroaches comprised approximately 44% of all removed items.  

Management Options

Killing the insect facilitates relief of symptoms and eventual removal. The insect must be immobilized prior to extracting it from the ear; however, one cannot just spray a can of Raid down the patient’s ear canal. The ideal agent used should not irritate the ear canal skin and it should reduce ear canal edema, have minimal toxicity as the tympanic membrane may be perforated, and be readily available in the ED. Topical preparations that may be used to assist with removal are mineral oil or lidocaine. 

Mineral Oil vs. Lidocaine

Mineral oil is thought to coat the bug, causing asphyxiation, ultimately leading to its death. It may take a couple seconds where the insect may move around violently until it meets its demise. Lidocaine is thought to cause instant paralysis, facilitating removal. Some advocate lidocaine over mineral oil as removal of the insect is easier in an aqueous solution rather than oil. In a study comparing survival times of American cockroaches in various test solutions, microscope oil (a highly refined preparation of mineral oil) killed cockroaches faster than lidocaine 4% and lidocaine 1% with median survival times at 50, 70, and 82 seconds, respectively. Another study on American cockroaches was performed to evaluate the efficacy of microscope immersion oil, viscous lidocaine 2%, lidocaine 2%, and lidocaine 4%. The mean killing time was shortest for the microscope oil at 27.2 seconds, followed by lidocaine 4% at 40.4 seconds, viscous lidocaine 2% at 41.6 seconds, and lidocaine 2% at 42.6 seconds. 

A case report combined the use of 2% lidocaine and suction techniques to extract a cockroach from the patient’s ear. The lidocaine itself was ineffective at stunning or inciting its escape. Another case in a 25-year-old male used a 1% lidocaine wash followed by gauze soaked with EMLA cream, which facilitated and led to successful extraction of the cockroach.

The Controlled Trial We Didn’t Know We Needed 

In a case that attempted to settle the age-old question of which agent is the best for removing the common cockroach from the ear canal, lidocaine or mineral oil, a patient presented to the ED with a cockroach in each ear. One ear canal received mineral oil versus 2% lidocaine in the other ear. In the mineral oil treated ear, “the cockroach succumbed after a valiant but futile struggle…”; however, the removal of the insect required much dexterity. In the ear treated with lidocaine, the response was immediate as “…the roach exited the canal at a convulsive rate of speed and attempted to escape across the floor.” The cockroach was killed using the “…simple crush method.” The authors concluded that lidocaine should be used for the treatment of a problem, “…that has bugged mankind throughout recorded history.”

Another case report demonstrated the possible adverse effects of using lidocaine for bug removal. A 50-year-old woman presented to the ED with a complaint of “I have a bug in my ear.” The treating physician applied 2% lidocaine spray, killing it; however, the physician was unable to extricate the insect. Otolaryngology was consulted and at this time, the chief complaint was extreme dizziness. The large cockroach was removed and post removal, a small traumatic perforation of the tympanic membrane was observed. It was believed that the topical lidocaine caused the vertiginous symptoms seen in the patient. Due to potential risk, the author of this case report recommends abandoning the use of topical anesthetics to kill insects and using the mineral oil instead. 

The debate still remains on which is the best agent to use prior to extraction. 

The Debrief

• Foreign bodies in the ear are a common presentation to the ED
• Insect aural foreign bodies are common, with cockroaches making up a large percentage of insects identified
• Insects must be immobilized or killed prior to removal as this facilitates removal from the ear canal and diminishes the pain and distress associated with the removal
• In regard to cockroaches, mineral oil or lidocaine may be used prior to removal