How we smell
The loss of the ability to smell is called anosmia. Its more common type is hyposmia – a condition when the sense of smell is reduced, but not lost.
First, the molecules of the odor-emitting substance capture special receptors that are located on the nasal mucosa. Then the smell, converted into an impulse, goes from the receptors to the olfactory bulbs – bundles of neurons, where it is processed and analyzed. As a result of this complex process, we are able to sense, recognize and remember various smells and aromas. If at one of the stages of the path there is a failure, our ability to smell is impaired.
It is customary to distinguish three types of olfactory disorders:
- peripheral anosmia – associated with a decrease in the functions of olfactory receptors associated with damage to the nasal mucosa;
- conduction anosmia – failure of impulse transmission from the bulbs to the analyzer;
- central anosmia – information received from receptors is not perceived in the brain.
Why the sense of smell disappears
We risk losing the ability to perceive the smells around us for various reasons.
“Anosmia or hyposmia can occur with diseases of the nasal cavity (with viral infections, allergies, polyps), prolonged exposure to toxic gases or prolonged use of vasoconstrictor drugs,” says Elena Shirshova, head of the neurological department, doctor – neurologist of FNKTs FMBA of Russia. – In addition, a violation of the sense of smell can be a symptom of a brain tumor, infectious, vascular, degenerative diseases of the brain, traumatic brain injury.
The most common cause of the problem. The loss of the ability to sense and distinguish smells is most often associated with a disruption in the functioning of receptors that transmit an impulse to the brain. With colds, which, as a rule, are accompanied by a runny nose, the cause of a decrease in the sense of smell is the swelling of the mucous membrane and the release of a large amount of mucus. This secret is needed to prevent the penetration of pathogens into the body. In this case, the activity of the cilia of neurons can be blocked, which leads to a temporary loss of the ability to smell and taste – these parts of the receptors are interconnected. How quickly the sense of smell recovers after rhinitis largely depends on the individual characteristics of the organism. For some, the ability to capture aromas and odors returns after 3-6 days, while others will have to wait 2-3 weeks or even longer. This is most often the case with chronic diseases.
Parkinson’s disease, Alzheimer’s
Loss of smell is a typical symptom of Parkinson’s and Alzheimer’s. Often, the loss of the ability to sense smells becomes the very first symptom of the onset of irreversible processes in the brain. By their ability to recognize odors, specialists can even determine with a high degree of probability the risk of developing these serious ailments.
Loss of smell in these diseases is associated exclusively with the work of the nervous system – atrophic changes in the cerebral cortex. This pathological process disrupts the activity of the central part of the olfactory analyzer.
With age, the ability to sense and recognize odors decreases. Anosmia has been developing over the years. The loss of smell in this case is associated with atrophic changes, in which the cells of the nasal mucosa, which are responsible for smell recognition, die off. This process is gradual. At first, sensitivity to weak aromas disappears, and after a while a person loses the ability to pick up even very strong odors. Anosmia can also be accompanied by another unpleasant manifestation – loss of taste.
An alarming symptom in old age is a sharp loss of smell, especially in combination with forgetfulness, decreased concentration, frequent headaches. In this case, you need to urgently contact a specialist.
This disease is an overgrowth of the mucous membrane in the nasal cavity that wears benign character. Polyps in the nose become a mechanical obstruction to the passage of airflow. Because of this, the ability to sense and recognize odors can decrease over time, to the point of almost complete loss of smell. I must say that this process takes a long time. At the same time, most often, the ability to feel very strong odors, for example, ammonia, is still preserved.
With covid, anosmia is diagnosed much more often. “According to statistics, loss of smell is observed in 80% of patients with Covid-19, regardless of the severity of the disease,” says Elena Shirshova. – Scientists believe that the virus can damage the nerve cells responsible for smelling. Therefore, patients with coronavirus lose their sense of smell without experiencing problems with nasal congestion or runny nose. Anosmia can occur both in the acute period of infection and after it. For most people who have had coronavirus, anosmia goes away within two weeks after recovery, but in some cases, it may take several months to regain sensitivity to odors. It is important to note that if you have a history of chronic paranasal sinus disease, neurological diseases, trauma or surgery on the brain, the risk of complete or partial loss of smell increases forever. ”
Learn how to restore your sense of smell after covid.
To choose the right treatment tactics, you need to determine the cause of anosmia. Specialists have at their disposal modern diagnostic methods. If the cause of the loss of smell is not, for example, rhinitis or another ENT disease that the doctor can detect during a visual examination, the patient may be prescribed an X-ray examination of the paranasal sinuses, endoscopy of the nasal cavity, and olfactometry – special tests that determine the acuity of the sense of smell. If brain tumors are suspected, they are referred for computed tomography.
To cope with a problem at home is possible only if it is caused by a common cold. For the treatment of rhinitis and sinusitis, it is recommended to rinse the nose with sea water, antiseptics, decoctions of medicinal herbs. Drops and sprays are also prescribed, sometimes antibacterial and antimicrobial agents.
When anosmia is caused by other causes, more thorough therapy is required, often in a hospital setting. For example, if the loss of smell is associated with the presence of tumors, a deviated nasal septum, you cannot do without a surgical operation.
“In rare cases, the disease remains incurable, for example, if it is caused by genetic disorders in the development of the fetus or is associated with age-related changes in the structure of the nasal mucosa,” says Elena Shirshova. – In addition, the risk of loss of smell increases significantly with a long experience of active or passive smoking. As a rule, over time, smokers’ sense of smell diminishes significantly. ”