Dear Friends,
TGIF and welcome back to Dr Euan's Friday Blog!
Many of us (MOH reports 6 /10 Singaporeans) have been infected by the SARS COVID 2 virus! Despite a high rate of vaccination and boosters, it seems that the new Variants eg BA 4 & BA 5 are managing to evade the current vaccines! Thankfully, most of us have only suffered mild symptoms eg. sore throat, cough, stuffy nose & fever.
However, a small percentage of us lose our Olfactory senses (smell) and / or taste due to the COVID infection. This loss in sense of smell can be temporary or permanent.
So what should you do?
Q: How does a covid infection affect my sense of smell/taste?
Temporary loss of Olfaction or smell, also known as anosmia, or a reduction in the sense of smell (hyposmia) is the main neurological symptom and one of the earliest and most commonly reported indicators of COVID-19. Studies suggest anosmia better predicts the disease than other well-known symptoms such as fever and cough, but the underlying mechanisms for the cause of loss of smell in patients with COVID-19 have been unclear.
Recently, an international team of researchers led by neuroscientists at Harvard Medical School has identified the olfactory cell types in the upper nasal cavity most vulnerable to infection by SARS-CoV-2, the virus that causes COVID-19.
Surprisingly, sensory neurones that detect and transmit the sense of smell to the brain are not among the vulnerable cell types.
Besides COVID infection, there are also many other possible causes of Anosmia and Hyposmia, including head trauma, contrecoup neck injuries, sino-nasal infections and tumours, to name a few.
Q: How common is anosmia?
A majority of COVID-19 patients experience some level of anosmia, most often temporary. Analyses of electronic health records indicate that COVID-19 patients are 27 times more likely to have smell loss but are only around 2.2 to 2.6 times more likely to have a fever, cough or respiratory difficulty, compared to patients without COVID-19.
Some studies have hinted that anosmia in COVID-19 differs from anosmia caused by other viral infections, including by other coronaviruses. For example, COVID-19 patients typically recover their sense of smell over the course of weeks—much faster than the months it can take to recover from anosmia caused by a subset of viral infections known to directly damage olfactory sensory neurons. In addition, many viruses cause temporary loss of smell by triggering upper respiratory issues such as a stuffy nose. Some COVID-19 patients, however, experience anosmia without any nasal obstruction.
Q: Will I be able to recover my sense of smell/taste?
Persistent COVID-19–related anosmia has an excellent prognosis with nearly complete recovery at 1 year.
As clinicians manage an increasing number of people with the post-COVID syndrome, data on long-term outcomes are needed for informed prognostication and counselling. In other words, time will tell!
Don't forget that almost any Acute Respiratory Virus Infection (ARI) virus can induce a loss of smell and/ or taste, and not just the COVID / SARS COV-2 virus 🦠
Q: When should I see a doctor about anosmia?
As there appears to be a relatively common sequela of the COVID / SARS COV -2 infection, most cases (90%) will spontaneously recover over time, usually within 4 to 6 weeks of onset.
If your anosmia / hyposmia persists for more than 1 month, then you can consult your GP / ENT Specialist for further investigations. Perhaps you can do a Naso-endoscopy to rule out any other causes of the hyposmia/ anosmia.
A doctor may perform a nasoendoscopy to observe the nose & airways for determining the cause of anosmia
Q: How can I tell if I have recovered my sense of smell?
There are also some SMELL KITs to test your sense of smell eg. including the U PENN smell test kit; The University of Pennsylvania Smell Identification Test (UPSIT) is a test that is commercially available for smell identification to test the function of an individual's olfactory system. Known for its accuracy among smell identification tests it is considered to be one of the most reliable (r=. 94) and trusted.
You can use a smell test kit with different essential oils to test your sense of smell
Q: How can I treat my anosmia?
Your sense of smell can be recovered through what's known as smell therapy.
The BBC has highlighted this issue in 2021, do have a read of the BBC article:
This is a process that involves sniffing different odours over a period of months to retrain the brain to recognise different scents.
A group of international experts say that smell training is cheap and simple. And unlike steroids, it is free from potential side effects.
A loss of smell is one of the main symptoms of coronavirus infection, along with a fever and a persistent cough. some common sentiments of patients who suffer from POST covid loss of smell and/ or taste are:
'The smells and tastes we still miss, long after Covid'
'Since I had Covid, food makes me want to vomit'
Covid-19 smell loss 'made meat taste like petrol'
In most cases, loss of smell will return relatively quickly after the illness has passed.
But around one in five people report they are still having problems eight weeks after falling ill.
One treatment that has been prescribed by doctors is a course of drugs known as corticosteroids, which lower inflammation in the body and are already used to treat conditions such as asthma.
Smell therapy provides a safe and simple way for our patients to "re-learn" how to smell.
Smell therapy can "retrain" the brain to remember certain scents over time
In a recent paper published in the journal International Forum of Allergy & Rhinology, the researchers suggest "smell training". This involves sniffing four things that have a distinctive, easily identifiable, and familiar smell - for example, oranges, mint, garlic, and coffee - twice a day for several months.
Prof Philpott said research shows that 90% of people fully recover their sense of smell after six months.
If it doesn't return, he says "smell training" helps to retrain the brain's smell pathways to recognise different odours. "It aims to help recovery based on neuroplasticity - the brain's ability to reorganise itself to compensate for a change or injury," he said.
Well, I hope this post has given you a little insight into the issue of COVID-related hyposmia & anosmia.
If you are interested, and would like to see Dr Euan about your Post-Covid loss in sense of smell, you can contact us at Euan's ENT Surgery & Clinic to make an appointment. We now also have smell test kits in clinic for you to try.
If you are keen to delve deeper into the topic, here are some useful references you can look up!
Meanwhile, here's wishing you a relaxing and peaceful weekend, to enjoy your favourite food and drink items!
References :
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