An observational study of 219 unvaccinated long-COVID patients with neurologic symptoms in the Amazon concludes that 64% had a persistently impaired sense of smell, which the authors said could be permanent.
Brazilian researchers evaluated 219 adult long-COVID patients at a rehabilitation center at a public university in the Amazon from Sep 9, 2020, to Oct 20, 2021. A total of 74.9% of the patients were women, 88.6% were 18 to 59 years old, 94.1% had more than 9 years of education, and 52.5% had a monthly income of up to US $192.
Most had likely been infected with wild-type SARS-CoV-2 because symptom onset occurred in spring 2020. Participants underwent neurologic examination and completed a questionnaire about their daily activities.
Hazard detection, food intake affected
Of the 219 patients, 139 (63.5%) were diagnosed as having some degree of chronic olfactory dysfunction (anosmia [loss of smell] or hyposmia [decreased sense of smell]), per the Connecticut Chemosensory Clinical Research Center test.
Patients with an impaired sense of smell had long-COVID symptoms for significantly longer than those with normal olfaction (average days, 242.7 vs 221.0), and a higher proportion had neurologic symptoms for more than 6 months (79.1% vs 63.8%).
There was a significant link between anosmia and interference with daily activities, namely impaired hazard detection, personal hygiene, and food intake (all 67.7%). More participants with a normal sense of smell than those with impaired olfaction reported headache (53.8% vs 37.4%), sleep disorders (36.3% vs 23.0%), and anxiety (45.0% vs 21.6%), while a greater proportion of the anosmia group also lost their ability to taste (ageusia, 59.7% vs 23.8%).
Hospitalization rates didn't differ significantly between participants with normal or impaired olfaction (20.0% vs 13.7%).
Condition may last more than 1 year
The study authors noted that most COVID-related olfactory disorders last only 2 or 3 weeks. But chronic olfactory disorders, they said, have been linked to disturbed eating patterns, depression, and reduced quality of life and can lead to difficulties with cooking, health and nutrition maintenance, personal hygiene, and social relationships.
These patients are three times more likely to be endangered by smoke inhalation, delayed detection of gas leaks, and spoiled food, the authors said.
They called a reduced ability to smell "one of the most important long-term neurologic symptoms of COVID-19, with the highest prevalence seen among women, adults, and outpatients. Patients with olfactory dysfunction may experience persistent severe hyposmia or anosmia more than 1 year from the onset of symptoms, suggesting the possibility of the condition becoming a permanent sequela."
The findings underscore the need for continued monitoring of the rate of recovery of olfactory function in long-COVID patients, the researchers said. "In addition, clinical trials and longitudinal studies are recommended to verify the effectiveness of potential treatments and the postulated risk for an increase in neurologic sequelae or neurodegenerative disorders in this population," they wrote.
FAQs
An observational study of 219 unvaccinated long-COVID patients with neurologic symptoms in the Amazon concludes that 64% had a persistently impaired sense of smell, which the authors said could be permanent.
Can Covid make you lose your smell permanently? ›
Earlier research conducted by our team revealed that two years after infection, 7.5% of people who developed smell loss from COVID-19 had not regained the sense, and 54% only partially recovered it. Smell and taste loss can take a significant toll on quality of life in many different ways.
How do I regain my sense of smell after long Covid? ›
Smell therapy can help – the process involves smelling different strong scents for at least 20 seconds while thinking about memories and experiences involving the scent. We generally recommend rose, lemon, clove and eucalyptus essential oils because the smells are strong and distinctive.
How do I retrain my sense of smell after Covid? ›
The essential oils are: rose, citronel (citrus or lemon), eucalyptus (menthol), and cinnamon. In order to perform smell retraining, you should smell each essential oil twice a day for 6 weeks.
How do I get my smell back? ›
Sniffing peanut butter, peppermint, and other strong scents may help you retrain your brain and restore your sense of smell. Your smell sense gives you a superpower.
Can loss of smell be permanent? ›
Usually, anosmia and hyposmia improve once doctors have treated the cause. In some cases, loss of smell can be permanent. If you notice symptoms of anosmia, it is important to seek treatment right away. Delaying treatment may result in permanent smell loss.
Can COVID cause loss of smell neurological? ›
Published in eClinicalMedicine, the observational study found that the people with long Covid smell loss had reduced brain activity and impaired communication between two parts of the brain which process important smell information: the orbitofrontal cortex and the pre-frontal cortex.
Can Flonase restore sense of smell? ›
Our study showed that olfactory and taste function significantly improved in patients with COVID-19. For all anosmia and dysgeusia cases who received fluticasone nasal spray and triamcinolone medications the recovery of smell senses and the taste was within a week.
What vitamins help regain taste and smell? ›
How does treatment to regain taste and smell begin? Rosen: First, we prescribe an oral steroid, work with patients through olfactory training (smell training), and suggest they begin taking supplements, such as V vitamin A, alpha-lipoic acid, sodium citrate, or omega 3.
Will my sense of smell come back? ›
Anosmia means you've lost your sense of smell. Often, it's a side effect of common medical issues like colds, seasonal allergies or polyps in your nose. Your sense of smell usually comes back once the underlying issue goes away or you receive treatment. Sometimes anosmia doesn't go away.
Implicit odor memory
Implicit memories of stimuli do not require conscious recollection of the initial encounter of the stimulus. In regards to olfactory memory, deliberate recollection of an odor experience is not necessary in order for implicit memories of odors to form in the brain.
Do essential oils work if you can't smell? ›
Scents still follow the same pathways into the brain even if you cannot perceive the odor, so yes, you can still benefit from aromatherapy even with anosmia.
How do you stimulate the olfactory nerve? ›
It is best to start with at least four different scents, especially smells you remember. The most recommended fragrances are rose (floral), lemon (fruity), cloves (spicy), and eucalyptus (resinous). Take sniffs of each scent for 10 to 20 seconds at least once or twice a day.
Does nasal spray help regain smell? ›
Fortunately, most patients with COVID-19 recover their sense of smell when congestion resolves however some do not. So, what do you do if you notice difficulty with your ability to taste or smell? Consider gently and safely clearing out your nasal passages using normal saline nasal spray or a Nettie pot.
How can I regain my sense of smell and taste allergies? ›
Nasal irrigation: Rinsing your nasal passages can help remove debris and excess mucus. Clearing your airways makes breathing easier, which can improve your sense of smell and taste. Nasal irrigation is often performed with simple devices, such as a neti pot.
What is the long term loss of smell? ›
Our sense of smell fades as we age, so people age 50 and older may have long-lasting anosmia. In some cases, anosmia may be a symptom of other, more serious medical issues like a traumatic brain injury (TBI).
Can loss of smell be reversed? ›
Olfactory neurons can regenerate
The nerve cells servicing the olfactory epithelium are unique to the nervous system. Unlike nerve cells anywhere else in the body, the olfactory neurons are able to recover or regenerate after injury. This means that incidences of anosmia can be temporary.
What are the long term symptoms of Covid 19? ›
Neurological symptoms or mental health conditions, including difficulty thinking or concentrating, headache, sleep problems, dizziness when you stand, pins-and-needles feeling, loss of smell or taste, and depression or anxiety. Joint or muscle pain.
How do you fix Parosmia after Covid? ›
Although this was a small sample size, this is the first study to suggest that gabapentin could be helpful in the treatment of COVID19‐related parosmia. Overall, the medication was well tolerated, with only one major adverse effect: daytime drowsiness.
