The Laryngoscope Lippincott Williams & Wilkins, Inc., Philadelphia © 2001 The American Laryngological, Rhinological and Otological Society, Inc. Insecticidal Activity of Common Reagents for Insect Foreign Bodies of the Ear Patrick J. Antonelli, MD; Anis Ahmadi, BS; Angela Prevatt, BS Objective: Insects commonly present as painful and distressing foreign bodies of the external ear ca- nal. Removing live insects can be challenging, espe- cially for primary care physicians who have limited equipment. The purpose of this study is to compare the insecticidal activity of commonly available prep- arations for insects that are most frequently recov- ered from ear canals: cockroaches (German and American), ticks, beetles, and honeybees. Study De- sign: Prospective, blinded. Methods: One hundred sev- enty insects of each species were placed in test tubes and submerged in 17 test preparations (10 tubes per preparation, 1 insect per test tube). Insect activity was stimulated by agitation of the test tube. Re- sponses were monitored, and the time until death was measured. Results: Most test preparations exhibited some insecticidal activity against most insect species. Ticks were completely resistant to all of the test re- agents. Ethanol killed the American cockroaches (mean time, 32.6 s), German cockroaches (mean time, 29.6 s), and honeybees (mean time, 19.6 s) the most rapidly. Conclusion: Many commonly available re- agents may be used to kill or immobilize insect for- eign bodies of the ear. Key Words: Insect, foreign body, treatment. Laryngoscope, 111:15–20, 2001 INTRODUCTION Insect and arachnid foreign bodies of the external auditory canal can cause patients great distress as a re- sult of otalgia and tinnitus. Rapid inactivation (killing) of the insect can facilitate relief of symptoms, as well as insect removal. Killing of insects within the ear canal is most readily accomplished by instillation of an insecticidal preparation. However, one cannot simply apply any household insecticide to the ear. A number of considerations restrict the use of exter- nal ear preparations. First, they should not irritate the ear canal skin. To the contrary, the ideal preparation would provide some degree of anesthesia to facilitate re- moval. Second, attempted foreign body extraction by an inexperienced clinician may induce ear canal edema, fur- ther complicating insect removal. An ideal preparation should, if anything, reduce canal edema. Third, the tym- panic membrane may be perforated by the insect or by the clinician (during the course of manual extraction) or be- fore acquisition of the insect foreign body. Hence, prepa- rations should have minimal toxicity or other side effects on the inner ear. Fourth, the ideal preparation should be readily available in most clinics, emergency rooms, and hospitals. With these considerations in mind, we hypothesized that topical cocaine or the combination of tetracaine and epinephrine may be the ideal solution to facilitate the killing and removal of insect foreign bodies of the external auditory canal. The purpose of this study was to compare objectively the insecticidal activity of these solutions against other widely available reagents for the most com- mon insect foreign bodies of the ear canal. PATIENTS AND METHODS Incidence of Aural “Insect” Foreign Bodies A retrospective chart review was performed on all patients treated for foreign bodies of the ear in the years 1992 to 1999. Patients were identified through a query of outpatient billing records at Shands Hospital at the University of Florida. Patients of all ages were included. No patients were excluded. For the purposes of this study, the term “insect” was used to include arachnids, such as spiders and ticks. The insects most commonly encountered in this review, in conjunction with a review of the literature, were included in the subsequent measurement of in- secticidal activity. Survey on Availability of Solutions and Chemicals An informal survey was performed to determine which prep- arations were most commonly available to emergency room per- sonnel. Facilities throughout the United States were identified through the 1998 Profiles of U.S. Hospitals. 1 Emergency depart- ment head nurses were asked to confirm their inventory of chem- icals, oils, gases, and solutions available in their facilities. Then the most widely available preparations were tested for insecti- cidal activity. Presented as a Poster at the Annual Meeting of the American Lar- yngological, Rhinological and Otological Society, Inc., Orlando, Florida, May 16, 2000. From the Department of Otolaryngology, University of Florida, Gainesville, Florida. Editor’s Note: This Manuscript was accepted for publication October 6, 2000. Send Correspondence to Patrick J. Antonelli, MD, FACS, Depart- ment of Otolaryngology, University of Florida, Box 100264, 1600 South- west Archer Road, Gainesville, FL 32610-0264, U.S.A. Laryngoscope 111: January 2001 Antonelli et al.: Insect Foreign Bodies of Ear 15