Why does the loss of smell occur?
The smell is a complex system that begins in the nose and transmits through nerve impulses the olfactory sensations until the brain, which processes them. If there is any alteration or interruption along this route, the sense of smell can be affected and even completely abolished.. When a person, for whatever reason, stops perceiving odors, they are said to have anosmia.
Causes that cause loss of smell
The causes of anosmia can be multiple, everything that may affect this information transmission process in any of its stages. Some people have anosmia congenital, for alterations at the level of olfactory receptors or the brain structures that process them, but most cases of anosmia are usually acquired, some reversible and some not.
The main causes of anosmia, within the multiple possible, are:
- Congenital
-
Infectious and inflammatory:
- acute or chronic
- Acute or chronic rhinitis
- Catarrh of the highways
-
Structural:
- Nasal polyps
- Nasal septum deviations
- Intranasal tumors
- Foreign bodies in the nose
- Rhinoplasty
-
Neurological:
- Degeneration due to age
- Multisystemic atrophy
- Huntington's disease
- Brain aneurysm
- Cerebrovascular accidents
- Brain tumor
- Malnutrition
- Zinc deficiency
- Vitamin B1 deficiency (Wernicke's disease)
- Brain surgery
- with brain damage
- Brain radiation therapy
Symptoms of loss of smell
The clinic of anosmia is evident, the absence of smell perception. The onset can be abrupt or more insidious and depending on the cause, other accompanying symptoms will appear. In addition, the wide variety of possible causes makes the range of accompanying symptoms of anosmia very extensive, but precisely this fact can help to better identify the probable cause of the olfactory deficit.
In the infectious anosmias there is usually:
- Rhinorrhea
- Increased mucus
- Cough
- General discomfort
- Fever
- Sense of occupation at the level of the nostrils.
- Occasionally, both in infectious and inflammatory causes as well as in structural ones, there may be nasal bleeding (epistaxis).
Before a patient with anosmia it is essential to make a good questioning to assess symptoms companions, investigating the onset of the lack of smell, distinguishing whether it is really total or only partial, and assessing traumatic antecedents or previous episodes. It is convenient to carry out a examination of the inside of the nostrils with a rhinoscope to observe the nasal mucosa and see if it is inflamed, if there is an excess of mucus or if there is something that obstructs the nasal passage.
Depending on the diagnostic suspicion, one or other tests will be carried out, such as a blood test, x-rays of the nasal sinuses, a computerized axial tomography () or a magnetic resonance imaging (MRI).
Treatment for loss of smell
Treatment of anosmia will differ greatly based on the underlying cause of it.
- In the case of anosmia of infectious origin, it will be treated with anti-inflammatories, antihistamines and, if necessary, intranasal corticosteroids and antibiotics.
- Anosmias of obstructive origin caused by nasal polyps, growths, or deviations of the nasal septum They will be corrected by surgical intervention, a procedure that may also be necessary in the case of chronic sinusitis.
- Anosmias by nutritional or trace element deficiencies they must be corrected with the contribution of the deficient substance.
- Those anosmias of neurological origin they may have a worse prognosis and the treatment will be essentially that of the underlying neurological disease.
- The congenital anosmias and those due to brain damage in the areas that process olfactory information have no treatment.
Due to the wide variety of causes, there are no specific recommendations to avoid anosmia. In case of presenting it and it is not due to an evident and transitory cause such as a catarrhal or flu, it is important to contact an otolaryngologist.
Did you know that we can distinguish up to 10,000 fragrances?
The olfactory sensation journey begins when the olfactory receptors, found in the yellow pituitary gland of the nose, are stimulated by volatile substances of a certain odor. There are 7 different types of olfactory nerve receptors whose combined stimulation allows distinguishing up to 10,000 different fragrances:
- Camphorated
- Musky
- Ethereal
- Floral
- Mentholated
- Spicy
- Putrid
This triggers a nerve impulse that is transmitted by the olfactory nerve or first cranial nerve, which passes through the wall of the skull and transmits the information to the olfactory bulb, first stop of olfactory reception, and from there the information is first transmitted to the hypothalamus and then to the cerebral cortex, which is when the smell becomes conscious.
What you should know:
- Anosmia is the absence of perception of odors due to an alteration in the olfactory path.
- Causes: congenital, infectious and inflammatory, structural or neurological.
- Treatment for anosmia will differ greatly depending on the cause.
(Updated at Apr 14 / 2024)