Table of contents:
- Main symptoms
- How to confirm the diagnosis
- Possible causes
- Can COVID-19 infection cause parosmia?
- How the treatment is done
Parosmia is a disorder of smell in which there is difficulty in identifying smells, and there may be a change in your perception, causing smells that were previously normal or pleasant, to be felt as unpleasant or unbearable. As smell is directly related to taste, in some cases the person who suffers from parosmia may also feel that a food that was previously appetizing becomes unpleasant.
This disorder occurs due to damage to the olfactory nerves that carry signals to the brain to identify smells, usually caused by bacterial or viral infections of the respiratory tract, such as sinusitis, the common cold, or COVID-19.
The diagnosis of parosmia is made by the general practitioner or the otolaryngologist through tests to identify the cause and, thus, start the most appropriate treatment, which can be done with drugs or olfactory training.
The main symptom of parosmia is the temporary disturbance of smell, which leads to a difficulty in recognizing or perceiving smells or aromas, in which normal and pleasant smells are perceived as unpleasant or unbearable, like the smell of food or perfumes, for example.
In addition, the person may have difficulty eating or feel nauseated when eating, as smell and taste are directly related, leading to loss of appetite and weight.
Parosmia can also affect a person's quality of life, due to a change in the sensation of smells, which can lead to mood swings, anxiety or depression.
How to confirm the diagnosis
The diagnosis of parosmia is made by the otolaryngologist or general practitioner by evaluating symptoms and clinical history of recent infections, lifestyle habits such as smoking or medication use, and family history of neurological diseases or cancer.
Although there is no specific test for parosmia, the doctor can do a smell test in which different substances are presented so that the person can identify and describe the smell.
Other tests that the doctor may order are computed tomography, magnetic resonance imaging or even a nasal biopsy to identify whether the parosmia may have been caused by neurological diseases or cancer.
Parosmia is caused by damage to the olfactory nerves, responsible for sending signals to the brain to identify smells, altering the way smells reach the brain.
Some conditions can damage the olfactory nerves and lead to parosmia, the main ones being:
- Common cold;
- Exposure and inhalation of smoke;
- Smoking habit;
- Parkinson's Disease;
- Brain trauma;
- Huntington's Disease;
- Brain or olfactory nerve tumor;
- Chemotherapy or radiation therapy for cancer treatment.
It is important to consult an otorhinolaryngologist or general practitioner whenever the smell disorder appears, to diagnose the possible cause and initiate the most appropriate treatment.
Can COVID-19 infection cause parosmia?
Some studies [1, 2] show that some people may develop parosmia while recovering from the loss of smell caused by COVID-19, due to the damage to the olfactory nerves caused by the coronavirus.
Although rare, parosmia can appear about 1 to 2 months after the initial coronavirus infection and persist for about 8 months or more, causing a rancid or rotting meat-like smell, affecting quality person's life.
How the treatment is done
The treatment of parosmia varies according to the cause, and in cases where the parosmia was caused by factors such as smoking, drug use or cancer treatment, when you stop using these substances, your sense of smell may return. to normal without the need for treatment.
However, when parosmia is persistent, your doctor may recommend taking medications such as clonazepam, phenytoin, topiramate, or valproic acid to help relieve symptoms.
In cases of parosmia caused by COVID-19, it usually improves on its own over time without the need for treatment. However, you can do olfactory training while the person recovers.
To do the olfactory training, you should choose 3 or 4 different scents, such as lemon, rose, clove and eucalyptus essential oils, for example, breathing deeply for 20 seconds at a time, at least 2 times a day, for about 3 months or more.However, despite being able to help in the recovery of smell, olfactory training still needs more scientific research to prove its effectiveness.