Distortion and loss of smell after Covid: Smell training can help, expert says

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  • Hundreds of thousands people are living with long Covid-related anosmia or parosmia.
  • However, time and smell training have been proven to work, says an SA ENT.
  • Together with his son, he’s developed a smell training app and put together a practical smell-training kit.

“I don’t want to cook dinner or prepare food anymore. It just makes me feel negative.” 

“I get headaches when triggered by certain smells. I hate the smell of food now, especially boiled chicken or meat.”

“Recently, we had a fire in our complex. I didn’t smell a thing.”

These are just some of the many reactions of people who have lost their sense of smell (anosmia), or have a distorted sense of smell (parosmia) months after their Covid infections have passed. These two smell disorders are common symptoms of long Covid.

Both conditions are frequency diagnosed among long-haulers and can have a profound effect on their quality of life.

Smell training can help

The technique involves actively sniffing four distinct scents every day for 20 seconds, for at least three months. Best of all, it is cheap, doesn’t require a prescription, can easily be done at home, and, unlike steroids, has no potential harmful side effects.

An ENT (ear, nose and throat) surgeon in South Africa has gone the extra mile to help sufferers by assembling a local smell training kit, together with a smartphone app.

“Most of the kits are available in the UK and US. And by the time you’ve got one of those kits shipped over here, it’s going to cost you R1 500,” says Dr Martin Young, who is based in Knysna. 

To date, he’s sold just over 300 kits. Priced at R299, Young breaks even, just covering the costs. You can also put together your own kit with essential oils you can buy at a pharmacy or by using common household items like dishwashing liquid or coffee beans.

However, what’s important is that the strength of the smells have to be consistent, Young cautions. “If you take coffee grounds and put them in a jar and smell them a week or two later, the grounds may have lost their smell, and you won’t know it. That’s one advantage of using the kits,” he says.

The smartphone app, named Smell Sense, is available to Android and iOS users and was developed by Young’s son, Matthew, who has a computer science degree. “This is his first smartphone app he’s ever built, and he did it from scratch,” says Young. 

Our brains can restore lost functions 

A person with anosmia or parosmia has nerve damage, and to a certain extent brain damage, affecting their smell sensorineural systems, explains Young.   

But there is good news: “Our brains also have an unbelievable ability to restore function to lost or damaged centres following injury or infection like that caused by Covid.”

Physiotherapists and occupational therapists train patients by encouraging this ability, known as neuroplasticity, in other functions of the brain, he explains. “They do this by teaching other areas of brain cells and their connections to take over the lost functions. The same can be done for anosmia and parosmia.” 

He adds: “Functional MRI studies of the brain have shown that even in people with anosmia, their olfactory centres light up on scanning when given something to smell. So, the nerve signals are getting there, but for some reason, the right smell sensations are not being generated. So we need to enhance neuroplasticity in order to get the ‘correct’ sensations to awaken in the affected olfactory centres in the brain.” 

Doing it right

For smell training to be effective, the person must complete the exercise when they are undisturbed and undistracted, and use both visual cues and memories to "awaken" the correct smell sensations, explains Young. This is why the app, which helps people smell-train with the process of neuroplasticity, has photographs and asks the user certain questions, such as: "Can you recall your last vivid memory of this smell?"

smell training
A screenshot showing one of the questions displayed in the Smell Sense app.

For the vast majority of people, time will heal the condition, he says. But smell training, while not a cure, can speed up recovery – if done correctly.   

Most people who give up smell training give it up way too soon, says Young, and stresses the minimum three-month period. “The total amount of time comes to around nine hours in time. But you can’t take a stroke patient and give them occupational therapy for nine hours and expect them to walk and talk again.” The same applies to smell training. “You’ve got to do it over time to allow the brain to make those associations,” he says. 

Be careful of some 'treatments' 

Smell training is the only method to be evidence-backed and has been shown under high quality trials to be effective, says Young. There are two particular international research groups known as Fifth Sense (in the UK), and AbScent, who have shown that smell training is a therapy that can help people with anosmia or paromia recover faster.  

“A person who doesn’t have anosmia or parosmia may not realise just how miserable the condition can make you. The larger Facebook support groups have 100–200 posts a day, and people are desperately miserable [for solutions]. And desperately miserable people will turn to any possible source of help,” says Young. 

From multivitamins and supplements to steroids and nasal phototherapy, there are people trying to take advantage of, and intentionally deceiving people with these conditions. “There are a lot of people who will talk about these various therapies, but very few of which have science to back them,” warns Young. 

Message of encouragement

Young acknowledges a lack of support for people living with anosmia or parosmia.

“These people go through absolute hell, and because they’re able to walk around and function, and they look ‘normal’ – it’s not as if they look sick – many of them don’t get the understanding and support that they need from their spouses, family, and work colleagues. It’s kind of a ‘pull yourself together’ kind of message, and that’s not fair,” he says.

For some sufferers of the condition, there has also been a lack of support from their doctors. Says Young: "A doctor's role is to diagnose, sometimes treat, always comfort, and always reassure.

"And what you’ve got to do with these patients is give them coping mechanisms for coping around [unpleasant] smells. One would be a simple, practical tool like nose clips," so that it reduces undesired odours when needing to cook, for example.

For those living with long Covid-related anosmia or parosmia, Young says: “Don’t give up hope until you’ve gone at least two years with this.” 

Here are some tips from Young on how to get the most out of smell training: 

  • Set aside a regular time to do your training and stick to it. My suggestion is first thing in the morning and last thing at night.
  • Don’t be distracted during this time. Your brain is under therapy and needs to pay attention to the smells you are receiving.  
  • Smell training has to be consistent. Most advocates suggest a minimum of three months before losing hope in the process. Remember, you cannot speed this process up – your brain is rewiring itself to repair the damage done by the virus.
  • Choose your scents. Most commercially available kits have lemon, rose, clove and eucalyptus. If your sense of smell can pick all of those up and not others, you want to train on the "others" – this will involve making up your own kits with the smells or closest equivalents that trigger your parosmia.
  • Pay attention to what it is you are doing. Having a "meditative" mindset is a very useful help.
  • Give yourself time and have realistic expectations. Many people recover to a normal or near-normal sense of smell without putting in any effort. That may take a year or longer.  
  • Avoid things that will affect your sense of smell under normal conditions, such as smoking, strong chemicals, etc.
  • See an ENT to confirm the diagnosis. Your lost sense of smell may be coincidental to having had Covid-19, and you might have another condition like nasal polyps. Having an ENT examine your nose and perhaps order a CT scan of your sinuses to exclude other pathology will be a great reassurance that you are on the right track with smell training.
  • Keep a diary reviewing your responses. The biggest benefit of this is that you can look back in time and review your own progress.

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READ | Smell training, not steroids, should be first treatment option for Covid-19 smell loss, experts say

READ | The loss of smell caused by Covid-19 doesn’t always go away quickly – but smell training may help

READ | Living with long Covid: Smell loss, hypertension, eye sensitivity – ‘This is not a friendly virus’


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