Anosmia refers to the complete loss of the sense of smell. It can be congenital, present from birth, or acquired. This disorder of the sense of smell has many causes and can have many consequences in daily life.
It should not be confused with hyposmia which refers to a weakening of the sense of smell.
What is anosmia?
Anosmia is a disorder of the sense of smell that results in the absence or complete loss of the sense of smell. It is usually bilateral, but can sometimes affect only one nostril.
What causes anosmia?
Anosmia can have a variety of causes. Depending on the case, loss of the sense of smell may be the result of:
- A congenital abnormality, present from birth.
- An acquired disorder.
The case of congenital anosmia
In some rare cases, anosmia is present from birth. Current scientific evidence suggests that it is a symptom of Kallmann’s syndrome, a genetic disorder of embryonic development.
The case of acquired anosmia
In most cases, anosmia is due to an acquired disorder. The loss of the sense of smell may be related to:
- A blockage of the nasal cavities that prevents the perception of odors.
- An alteration of the olfactory nerve that interrupts the transmission of olfactory information.
The obstruction of the nasal cavities can occur in several cases, such as:
- Rhinitis, an inflammation of the nasal mucosa that can have several causes, especially an allergic cause (allergic rhinitis).
- Sinusitis, an inflammation of the mucous membranes in the sinuses, the chronic form of which is most often the cause of anosmia.
- Sinonasal polyposis, which is the formation of polyps (outgrowths) on the mucous membranes inside the nasal cavities.
- A deviation of the nasal septum.
The olfactory nerve may be affected by:
- Certain drug treatments
- Certain infections, especially those caused by influenza viruses (flu), Coronaviruses (COVID-19), and herpes simplex viruses
- Viral hepatitis, inflammation of the liver caused by a virus
- Head trauma
- Meningiomas – tumors, often benign, that develop in the meninges, the membranes that cover the brain and spinal cord
- Neurological diseases.
What are the consequences of anosmia?
The development and consequences of anosmia vary from case to case. This disturbance of the sense of smell may be temporary if it is due to a temporary blockage of the nasal cavities. This is particularly the case with rhinitis.
In some cases, this disturbance of the sense of smell persists over time, which can interfere with the daily life of anosmic patients. Persistent or permanent anosmia can lead to:
- A sense of discomfort that, in the most severe cases, can lead to withdrawal and a depressive syndrome.
- Eating disorders that may be associated with ageusia, loss of taste.
- A safety problem due to the inability to recognize warning signs such as the smell of smoke.
- Poor hygiene related to the inability to detect bad smells.
Treatment of anosmia: what are the solutions for the loss of the sense of smell?
Treatment consists of treating the cause of anosmia. Depending on the diagnosis, various medical treatments can be considered:
- Treatment with medication, especially if there is inflammation or infection of the respiratory tract.
- Surgical intervention, especially if a tumor or blockages are detected.
- Follow-up care by a psychotherapist if the anosmia leads to psychological complications.