A numbing procedure usually used to treat pain and post-traumatic stress disorder is being tested as a way to restore smell and taste in people with long Covid.
It's called a stellate ganglion block. In the procedure, a doctor uses a temporary, local anesthetic — like what a dentist would give before filling a cavity — and injects it into a specific bundle of nerves called the stellate ganglion on both sides of a person's neck. The nerves are part of the sympathetic nervous system, which controls automatic bodily functions, such as blood pressure, digestion and heart rate.
The area is not known to have any impact on how a person perceives odors, however, leaving some experts skeptical of the approach. Other doctors say they have seen real improvements in patients who either can't smell anything or find previously delicious food and drinks now taste repulsive.
Smell disorders tend to become more common with age, and affect millions of people. As many as 1 out of every 8 people in America over age 40 have some kind of olfactory dysfunction, according to the National Institute on Deafness and Other Communication Disorders.
A survey last yearfound that about 15% of people with Covid-related olfactory loss still had trouble smelling correctly six months later.
Not many treatments are available for smell disorders. Doctors may try olfactory retraining, in which patients concentrate on sniffing four scents — usually rose, eucalyptus, lemon and clove — twice a day for at least three months. Smell therapy has shown promise in some clinical trials.
Getting smell back
At Cleveland Clinic, doctors are offering stellate ganglion blocks to long Covid patients, with the hope of launching a clinical trial.
Jennifer Henderson, 54, of Franklin, Ohio, got Covid in January 2021 and immediately lost the ability to taste or smell anything. A year later, her senses came back, but were wildly distorted.
She first tried olfactory retraining "religiously" for months, without success. Peanut butter and ranch dressing still smelled like chemicals.
Chicken was the worst, she said. "It tasted like rotting flesh. I had to spit it out."
Finally, in November last year, she received the stellate ganglion block at the Cleveland Clinic. The effect was immediate. She held a fresh cup of coffee up to her nose and burst into tears.
"It was the best smell ever," Henderson said. "I just cried like a baby."
Dr. Christina Shin, a physician specializing in pain management at the Cleveland Clinic, said that nearly every day at least one or two patients are referred to her from the long Covid clinic affiliated with the hospital system for help with their smell and taste.
She has treated roughly 30 long Covid patients with the block. About half get better, she estimates, though the level of improvement varies between 25% and 90%.
Dramatic responses like Henderson's have made the rounds on social media, igniting enthusiasm in long Covid communities. But many doctors are cautious because no one really understands how it works.
Some experts theorize that it may increase blood flow to the brain. Others suggest the block acts as a "reset button" for the sympathetic nervous system.
Some question whether it works at all.
"There is no scientific evidence that this is effective," said Dr. Justin Turner, an associate professorin the department of otolaryngology–head and neck surgery at Vanderbilt University Medical Center in Nashville, Tennessee.
"Given the lack of data suggesting efficacy, it's really hard to advocate for this for patients who have a problem that typically resolves with time," he said.
As many as 80% will recover on their own within about six months, said Dr. Zara Patel, a professor of otolaryngology at Stanford University.
That's because stem cells in the nasal cavity have the ability to turn into brand new olfactory receptor neurons that detect odors.
"Throughout our lifetime, probably every three to four months, each olfactory receptor neuron dies off, and a new olfactory receptor neuron comes in and takes its place," Patel said.
Sometimes those new neurons get confused after they regenerate, leading chicken to smell like rotten flesh, as in Henderson's case.
Distorted smell, called parosmia, isn't just about difficulty during mealtimes. The condition can have a profound and deeply upsetting impact on a person's life.
In 2021, researchers in the United Kingdom surveyed people with Covid-related parosmia. Some worried about the effect it had on how they felt about their children.
"A lot of my maternal bonding feelings for my children are tied up with smell," one woman said in the study.
Some reported that the problem was ruining their sex lives. One person wrote about a partner's "rotten breath." The stench was "unbearable, no matter how hard I tried to put it out of my mind."
Some patients fall into despair.
"I have had many patients crying in my office telling me that the parosmia — not just the smell loss, but the smell change — is destroying their life," said Dr. Nyssa Farrell, an assistant professor of otolaryngology-head & neck surgery at Washington University School of Medicine in St. Louis.
However, she was wary of anecdotes of people getting better after a stellate ganglion block.
"It kind of sounds like voodoo," Farrell said. "I'm a scientist and I don't just believe what people say."
With desperate patients in mind, she started a small study to see if the block would work well enough to justify launching a large, randomized clinical trial that would give the needed evidence.
Among 20 patients with trouble smelling correctly, 10 reported "slight to moderate" improvement after the stellate ganglion block. It wasn't a strong result, but enough to move forward "to see if this is a placebo effect or if this is real," Farrell said.
A larger study is in the planning stages.
A stellate ganglion block is not the only potential remedy under investigation for loss of smell. Patel, of Stanford, ran a study looking at whether an injection of platelet-rich plasma deep into the nasal cavity might help prompt olfactory neurons to form correctly.
The procedure involves drawing the patient's own blood, removing its red and white cells, leaving behind plasma full of platelets and growth factors known to regenerate different types of tissue.
"Hopefully, what platelet-rich plasma is doing," Patel said, is getting those neurons to regenerate in a way "so that the correct signal is sent back to the brain."
Among 26 study participants, those who got the plasma injection were 12 times more likely to report improvements in their smell loss than those who got placebo shots.
Patel is now offering the procedure to all of her patients who have lost smell.
Does smell treatment work?
Excitement for stellate ganglion blocks' potential for treating long Covid ramped up in December 2021 when Dr. Luke Liu, a pain specialist in Anchorage, Alaska, reported the successful treatment of two long Covid patients.
Many of their ongoing symptoms, including muscle pain, fatigue, dizziness, brain fog and loss of smell and taste, improved within a week of getting the injections, he said.
Liu theorizes that a "glitch" in the autonomic nervous system plays an important role in lingering Covid and similar post-viral illnesses.
"In the case of long Covid, that glitch prevents the nervous system, and probably the rest of the body, from healing itself from a viral infection," he suggested. "The stellate ganglion block acts by pushing the reset button to that system. By doing so, it allows the entire system to reboot and become more synchronized and organized."
Liu has treated roughly 300 patients, and says about 65-70% "do really well and don't need any other intervention."
Still, he cautioned, it's too early to call stellate ganglion blocks a cure. About 5% of patients, he said, don't have any lasting improvement. About a third must go back to the clinic every few weeks or months for additional injections.
Henderson, who was treated at the Cleveland Clinic, has had to return three times. Her smell and taste are better, she said, but not back to normal.
"This should be treated as a scientific clue rather than a solution at this point," Liu said, adding that larger studies are needed.
What are the risks of smell treatment?
The bundle of nerves targeted in the block procedure is right next to the carotid arteries, a pair of major vessels that supply blood to the brain. If inserted incorrectly, the medication can disrupt vocal chords and lead to trouble breathing.
The risks drop tremendously when a highly experienced doctor performs the stellate ganglion block, which has been used for decades by pain specialists to treat complex pain syndromes, Farrell said. She partnered with an anesthesiologist for her studies.
"She does stellate ganglion blocks for a living," Farrell said. "For her, the risks are very low."
The cost of the procedure varies widely and some insurance companies do not cover the block to treat smell disorders.
Liu said that he charges $500 per block, and is disheartened by anecdotes of other clinics billing their patients thousands of dollars.
"To me, this is taking advantage of people who are suffering."
CORRECTION (April 1, 2023, 11:50 a.m. ET): An earlier version of this article misspelled the name of the assistant professor of otolaryngology-head & neck surgery at Washington University School of Medicine in St. Louis. She is Dr. Nyssa Farrell, not Ferrell.
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FAQs
People with long Covid smell disorders or loss of taste may get relief with an experimental treatment? ›
A numbing procedure usually used to treat pain and post-traumatic stress disorder is being tested as a way to restore smell and taste in people with long Covid. It's called a stellate ganglion block.
How do I get my taste back after COVID long term? ›- learn about your condition from trustworthy sources.
- eat cool or room temperature foods.
- take small mouthfuls – don't give up too quickly as you may get used to the taste.
- try bland foods like rice, boiled potatoes and pasta.
- try flavours that appeal to you.
- keep trying things – what you like can change from week to week.
“We found that probably 80% of those patients who have a loss or distortion of their sense of smell will recover that sense about one to three months after the COVID-19 infection has resolved.
How to treat parosmia taste in COVID? ›Overall, gabapentin appears to be a well‐tolerated potential treatment option for parosmia in those infected with COVID‐19.
How long can it take to get your sense of smell and taste back after COVID? ›You might lose your sense of smell when you have COVID. We do not have a lot of information about how long it takes for COVID patients to get their sense of smell back. Research from other viruses that affect your sense of smell shows us that smell usually returns within two weeks but can sometimes take longer.
What can I do to restore my sense of smell and taste? ›- Line up four essential oils of your choosing. For example: oregano, lemon, eucalyptus and rosemary. ...
- Starting with the first scent, take gentle whiffs of it for 25 seconds. ...
- Give your brain one minute to process that scent. ...
- Do this exercise twice a day, morning and night, for three months.
Experiment with different foods
Plus, certain foods, such as sour and tart foods, can enhance and stimulate the taste buds. In this case, adding more citrus flavors (think lemon, orange, lime) may help. Also, certain spices, herbs, vinegars, and seasonings may help boost the taste of your meal ( 6 , 7 ).
Some people experience a change to their taste and smell following COVID-19 infection, also known as parosmia (abnormal sense of smell), hyposmia (decreased sense of smell), and anosmia (loss of sense of smell). The good news is it's usually only temporary—in most cases.
What helps regain taste and smell loss from 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 you fix Covid loss of smell? ›Olfactory retraining is the process of retraining your nose to smell. It involves smelling strong scents (citrus, cloves, eucalyptus) every day while thinking about what they smell like to try to help reform normal responses to your nose and brain. Research has shown it can improve parosmia in long COVID patients.
How do you treat long COVID taste? ›
A numbing procedure usually used to treat pain and post-traumatic stress disorder is being tested as a way to restore smell and taste in people with long Covid. It's called a stellate ganglion block.
How long does it take for olfactory nerves to regenerate after COVID? ›She knew that COVID-19-related smell loss also was a neurological problem, in which long-term effects of the virus prevent nerves deep in the nasal cavity from regenerating correctly. These nerves connect to the brain and normally regenerate every three to four months.
How do you get rid of a stuck smell in your nose? ›- Try a homemade saltwater rinse. Using a saltwater rinse can help temporarily reduce the intensity of a bad smell in the nose. ...
- Stay hydrated. Share on Pinterest Dehydration may cause conditions that result in a bad smell in the nose. ...
- Practice good dental hygiene. ...
- Use over-the-counter medications.
If a cold or flu caused ageusia, your taste may return after taking antihistamines or decongestants. Infections can be treated with antibiotics. Your healthcare provider can help determine which course of action to take. Once you've recovered from your illness, your sense of taste will likely return.
What to eat when you lose your taste from COVID? ›Try sharp tasting foods and drinks, such as citrus fruits, juices, sorbet, jelly, lemon mousse, fruit yoghurt, boiled sweets, mints, lemonade, Marmite, Bovril, or aniseed.
How do you know if you have long COVID? ›Symptoms of long COVID
extreme tiredness (fatigue) feeling short of breath. loss of smell. muscle aches.
- quitting smoking.
- improving dental hygiene by brushing, flossing, and using a medicated mouthwash daily.
- using over-the-counter antihistamines or vaporizers to reduce inflammation in the nose.
- Acknowledge your feelings about the loss.
- Consult with an ear, nose, and throat specialist for guidance.
- Consider adjusting your cooking in favor of spicier foods.
- Maintain hope for recovery.
- Cultivate a sense of gratitude: you have survived a potentially lethal disease.
Your sense of smell may go back to normal in a few weeks or months. Treating the cause might help. For example, steroid nasal sprays or drops might help if you have sinusitis or nasal polyps. A treatment called "smell training" can also help some people.
What supplements help taste buds? ›The treatment options for an impaired sense of taste depend on the exact cause for the dysgeusia or hypogeusia. With mineral or vitamin deficiencies, simply supplementing with a multi- or specific vitamin (B12, B-complex, and zinc) may be helpful.
Can taste buds be restored? ›
A taste bud is good at regenerating; its cells replace themselves every 1-2 weeks. This penchant for regeneration is why one recovers the ability to taste only a few days after burning the tongue on a hot beverage, according to Parnes. Aging may change that ability.
Is long COVID permanent? ›People with Long COVID can have a wide range of symptoms that can last weeks, months, or even years after infection. Sometimes the symptoms can even go away and come back again. For some people, Long COVID can last weeks, months, or years after COVID-19 illness and can sometimes result in disability.
What is the mystery of COVID-19 smell loss? ›The viral titer was the highest in the nasal cavity, where ACE2 expression was the lowest in the alveoli of the respiratory tract 50. Therefore, it is likely that the OM is the initial infection site for SARS-CoV-2 and manifests olfactory loss as one of the earliest symptoms of COVID-19.
Does Flonase help get smell back after COVID? ›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.
Is there a cure for parosmia? ›Yes. In some cases, parosmia is permanent. But full recovery is common.
What is olfactory retraining for COVID-19 patients? ›The training consists of smelling 4 scents (rose, eucalyptus, lemon, clove), 2 times a day and following these steps: Choose 1 scent and smell it for 15 seconds while trying to remember what it once smelled like. Rest for 10 seconds. Smell the next scent for 15 seconds.
Do your taste buds really change every 7 years? ›In conclusion, we were able to VERIFY the answer to Maddie's question is no. Taste buds don't change every seven years. They change every two weeks, but there are factors other than taste buds that decide whether you like a certain food.
What is Dysguesia? ›Dysgeusia is a taste disorder. People with the condition feel that all foods taste sour, sweet, bitter or metallic. Dysgeusia can be caused by many different factors, including infection, some medications and vitamin deficiencies.
What is smell therapy? ›Smell retraining therapy (SRT) is a treatment for loss of smell, also referred to as hyposmia or anosmia. It can be used to help return your sense of smell if it was lost during a viral infection or minor head trauma. SRT was originally developed in 2009 by Dr. Thomas Hummel at the University of Dresden.
How do you stimulate the olfactory nerve? ›Carry a vial of a nonirritating substance in your bag; vanilla, lemon, and freshly ground coffee are good examples, and tobacco or scented soap will do if necessary. These odors stimulate the olfactory receptors. Do not use irritating odors such as camphor or menthol.
How do you repair olfactory neurons? ›
Summary: Insulin plays a critical role in the maturation, after injury, of immature olfactory sensory neurons.
Why do I have a bad smell in my nose and taste in my mouth? ›Tooth infections, cavities and poor oral hygiene can all lead to a bad smell in the nose and a bad taste in the mouth. Plaque and bacteria have an odour and can travel through the mouth and reach the sinuses. Tooth decay traps bacteria that release gases that can also produce an unpleasant odour.
What deficiency causes loss of taste? ›Vitamin or mineral deficiencies—Deficiencies in the B vitamins, especially B12, as well as certain minerals like zinc have been associated with loss of taste.
What foods can you taste without smell? ›Without our sense of smell, our sense of taste is limited to only five distinct sensations: sweet, salty, sour, bitter and the newly discovered “umami” or savory sensation. All other flavours that we experience come from smell. This is why, when our nose is blocked, as by a cold, most foods seem bland or tasteless.
How do you taste with a blocked nose? ›The best place to start is focusing on reducing the inflammation in your nasal passages. If you can open up your sinuses and facilitate drainage, your smell (and therefore your taste) will return faster. Saline irrigations are helpful to wash out signs of infection and clear inflammation.
Is COVID-19 a complete loss of taste? ›As a result of COVID-19, affected people can experience chemosensory dysfunction in a variety of ways, including complete loss of smell or taste (anosmia or ageusia, respectively), partial loss of smell or taste (hyposmia or hypogeusia), and/or a distorted sense of smell or taste (e.g., parosmia, dysgeusia).
What is the last lingering symptom of COVID? ›Many adults experience problems like coughing, chest pain, and fatigue six months after their stay.
What does long COVID feel like? ›Chest pain after Covid
Chest pain is a very common symptom of long Covid. Some people are having chest pain that lasts beyond their initial Covid-19 infection, or that starts in the weeks after they've had the virus. It's important to remember that there are many different causes for chest pain.
- Exercise to help cope with COVID-19. ...
- Talk about your frustrations. ...
- Engage in constructive thinking. ...
- Practice mindfulness and gratitude. ...
- Take it day by day or even moment by moment. ...
- Be compassionate with yourself. ...
- Find things to look forward to.
As you age, you lose some of the olfactory nerve fibers in your nose. You have fewer taste buds, and the ones you have left aren't as sharp, especially over age 60. This often affects your ability to notice salty or sweet tastes first, but don't add more salt or sugar to your food. That could cause other health issues.
How long does coronavirus taste loss last? ›
Conclusion: The present study concludes that the onset of symptoms of loss of smell and taste, associated with COVID-19, occurs 4 to 5 days after other symptoms, and that these symptoms last from 7 to 14 days.
What can I eat to get my taste back? ›Try sharp tasting foods and drinks, such as citrus fruits, juices, sorbet, jelly, lemon mousse, fruit yoghurt, boiled sweets, mints, lemonade, Marmite, Bovril, or aniseed. Excessive sweetness can be relieved by diluting drinks with tonic or soda water. Adding ginger, nutmeg or cinnamon to puddings may be helpful.
Do taste buds grow back? ›Taste buds are cells on your tongue that allow you to perceive tastes, including sweet, salty, sour, bitter and umami. Taste buds regenerate approximately every 10 days, which means injured taste buds usually repair on their own.
What vitamin helps your taste buds? ›The treatment options for an impaired sense of taste depend on the exact cause for the dysgeusia or hypogeusia. With mineral or vitamin deficiencies, simply supplementing with a multi- or specific vitamin (B12, B-complex, and zinc) may be helpful.
What deficiency causes loss of taste and smell? ›It could have been worse—a severe vitamin B12 deficiency can lead to deep depression, paranoia and delusions, memory loss, incontinence, loss of taste and smell, and more.