Is loss of sense of smell after head trauma dangerous?

Question
Hello doctor,
My mother fell and hit her head on the wall of a car and lost her sense of smell and could not smell anything. The doctor asked me, is it dangerous to lose my sense of smell after a head injury? Thank you.
Tran Thi Yen (1992)
Answer
Answered by Specialist Doctor I Le Van Quang - Ear - Nose - Throat Doctor - Department of General Surgery, Vinmec Nha Trang International General Hospital.
Hello,
To the question "Is it dangerous to lose your sense of smell after a head injury?", the doctor would like to answer as follows:
About 5% to 20% of the total number of patients who visit specialized centers department with olfactory dysfunction diagnosed as post-traumatic disorder. Along with loss of smell following infection and sinus disease, head trauma is the most common cause of impaired sense of smell. Depending on the severity of the head injury, loss of the sense of smell can occur in up to 30% of cases.
The degree of recovery after traumatic loss of smell is about 10%. In most cases, it takes several months for the sense of smell to return. However, recovery from olfactory loss following trauma has been documented for 5.7 years after olfaction loss. You should take your mother to the doctor to investigate the extent, location and nature of the head injury, this issue cannot be concluded without investigation.
If you still have questions about loss of smell, you can go to a hospital of Vinmec Health System for further examination and advice. Thank you for trusting and sending questions to Vinmec. Wishing you lots of health.
Best regards!