Etiology
Foreign bodies in the external auditory canal are more common in children, often caused by small objects inserted while playing. In adults, it is mostly caused by small objects remained after ear picking or trauma. Foreign bodies can be animals, such as insects; plants, such as grains, beans, and small fruit kernels; and nonbiological objects, such as stones, iron filings, and glass beads.
Clinical manifestations
Adults can generally sense foreign bodies in the ear, while foreign bodies are usually discovered when children seek medical attention. Clinical manifestations vary depending on the size and type of foreign bodies. Small, nonirritating, nonbiological foreign bodies may not cause symptoms. Generally, large foreign bodies or foreign bodies close to the tympanic membrane cause apparent symptoms. Animal foreign bodies such as live insects can crawl, causing severe otalgia and noise and even damaging the tympanic membrane. Plant foreign bodies such as beans expand when exposed to water and block the external auditory canal, causing aural fullness, otalgia, hearing loss, and secondary external otitis. Foreign bodies that do not change in shape when exposed to water may remain in the external auditory canal without symptoms. The foreign bodies may be wrapped by cerumen, forming cerumen impaction. Sharp and hard foreign bodies may damage the tympanic membrane. Foreign bodies irritating the external auditory canal and tympanic membrane may occasionally cause reflex cough or dizziness.
Figure 1 Foreign body in the external auditory canal
Figure 2 Extraction of foreign bodies in the external auditory canal
Treatment
Different removal methods are used depending on the nature, shape, and location of the foreign bodies.
When the foreign body does not cross the isthmus of the external auditory canal or is not incarcerated in the external auditory canal, it can be directly extracted with a cerumen hook.
Since most insects cannot crawl backwards or rotate in the external auditory canal, the insects crawl continuously toward the tympanic membrane. Therefore, it is advisable to drip oil or ethanol into the ear, or place a cotton ball soaked in ether in the external auditory canal for few minutes to adhere, anesthetize, or kill the insect, and then extract the insect with tweezers or rinse the external auditory canal to remove the insect.
Hard spherical foreign bodies such as glass balls and round beads may be difficult to remove because they cannot be grasped firmly. Right-angle hook or suction tube can be used. If the foreign body is large and is deeply incarcerated in the external auditory canal, it is necessary to remove the foreign body under local or general anesthesia. If necessary, an incision in the ear may be performed, and even part of the bony posterior wall of the external auditory canal may need to be removed to facilitate the removal of the foreign body. In young children, foreign bodies should be removed under brief general anesthesia to avoid injury or pushing the foreign bodies more deeply due to incoordination during surgery.
In patients with secondary infection caused by foreign bodies in the external auditory canal, anti-infection treatment can be given, and then the foreign bodies can be removed after the inflammation subsides, or external otitis can be properly treated after the foreign bodies is removed.