2025 Volume 76 Issue 2 Pages 96-100
We herein report a case of a 72-year-old man who complained of recurrent hyperalgesia in the right big toe, which was successfully treated with the Kampo formulation ninjin’yoeito. The unusual pain felt like being cut with a utility knife whenever his skin was lightly scraped with a toothpick. There was mild tactile loss at this area, however, there were no other sensory disturbances in the sense of pain, cold, or vibration. This patient’s hobby was Iaido, a type of Kendo, which places stress on the soles of the feet. Therefore, we speculated that the clinical disorder in this case was related to his exercise. This patient exhibited a pattern of qi and blood deficiency with qi uprising, which suggested the use of ninjin’yoeito. After taking this Kampo formulation, his abnormal hyperalgesia with coldness in the big toe resolved. There have been no prior reports of ninjin’yoeito effectively treating unusual hyperalgesia.
