We report herein on a case of a copepod parasite identified in the left nasal cavity. An 80-year-old woman visited our hospital with a chief complaint of delusions of parasitosis of the nails, skin, and nasal cavity. A foreign body that looked like a worm was detected in the left nasal cavity and removed. This appeared to be a parasite called a copepod. The patient was diagnosed by the mental health department as having skin delusional parasitosis due to dementia. Although the route of infection to the nasal cavity is unknown, there is a possibility that the patient inserted the copepod into the nasal cavity herself, to justify her symptoms of delusions of parasitosis.
