‘Mentally, it’s excruciating’: Life without a sense of taste and smell

It’s something I heard a lot. “Well, if you had to lose one sense, that would be the one, wouldn’t it?” alongside “I don’t think it would bother me that much”. Back in 1998 I lost my sense of smell (and seemingly my sense of taste) to a virus. Now stories are circulating that one common symptom of Covid-19 is loss of taste and smell. It’s known as anosmia. Sounds minor – it isn’t.

It’s likely that most of the new cases we are seeing only involve loss of the sense of smell. We know Covid-19 resides in our airways and we know viruses can affect olfaction. But most of what we think of as taste is actually flavour detected by our olfactory system. So when we lose our sense of smell we also think we have lost our sense of taste too.

Our tongue can only detect sweet, salt, bitter, sour and umami. So when we eat a strawberry our taste buds tell us it’s sweet but it is actually our olfactory system that tells us the sweetness is strawberry-flavoured, rather than mango or nectarine. So even though we say we are “tasting” a strawberry, what we are experiencing is actually its flavour produced by the odour of the strawberry passing into our nasal cavities through the link between mouth and nose. This is why when we lose our sense of smell, we are also convinced we have lost our sense of taste as well. And to lose what seems like two of only five senses is not only disorienting, it can be devastating too.

But “it’s the only illness that when you tell people you have it, they’ll openly laugh”, a fellow sufferer told me at the outset. She was right. I once sat through a wedding dinner next to a guest who giggled throughout the meal after I told him I couldn’t taste it. I had to leave the room, a lesson learnt. I guess it’s one of those “if you’ve never had it, you can’t know” health problems (more of that below) but be in no doubt that mentally it’s excruciating.

Our sense of smell arises in a small patch of tissue high in the nasal cavity. This is the olfactory epithelium, which contains about 50 million nerve cells, or neurons, bristling with hair-like cilia that extend into the mucus lining the nose. Molecules from food or anything with an odour waft into the nose, dissolve in the mucus and bind to receptor proteins on the cilia, triggering an electrical impulse. The neurons send this signal through the olfactory nerve to the brain. It is only recently that the complexities of our olfactory system have been cracked – US researchers Richard Axel and Linda Buck won the 2004 Nobel prize for medicine, following their research into how the neurons of the epithelium identify different odours, but there’s much still to discover.

So how is Covid-19 attacking this olfactory system? Well, if this is indeed proving to be widespread, more study would be required, but any respiratory virus can cause anosmia if it penetrates the cells of your olfactory epithelium. It’s a rare but documented side effect of cold and flu viruses and now anecdotal evidence seems to suggest a particular propensity of Covid-19. In some cases it appears to be the only symptom in an otherwise asymptomatic infection.

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Viruses work by attaching themselves to proteins on our cells, entering them, replicating inside the cell and ultimately destroying the cell from within, a process called necrosis. A respiratory tract virus can break down cells all the way from your nose through your throat and airways to your lungs. But because the cells of your olfactory system also provide you with one of your senses, if the virus enters the olfactory epithelium then you can become anosmic.

The good news is that because the cells of the olfactory surfaces can regenerate, many people will recover spontaneously. The cells of the olfactory epithelium can be replaced within 30 days and olfaction returns. This has certainly been the case with anosmia caused by colds and flu and, again anecdotally, would appear to be the case with Covid-19 anosmia. The bad news is that in some people the virus penetrates so far that it damages the stem cells that the olfactory epithelium relies on for regeneration. In such cases recovery is impossible.

Opinion on recovery rates differs. A University of Dresden study says that only a third of viral anosmia sufferers recover full olfaction. Others report that anything between 18 and 66 per cent will recover. Yet another suggests that two-thirds of all viral anosmia victims will have regained at least some of their smell within four years. Bearing in mind that “some of your smell” is arguably as little as 1 per cent and that four years is a long time, this is not a good prognosis. However, many people will recover relatively quickly without reporting symptoms to a doctor so it is likely the figure will be much higher than studies have determined. Whatever the truth, though, a significant proportion of sufferers will never get their olfaction back.

And of those that do recover spontaneously there is often the strange sensation – known as parosmia – of returning flavours being distorted. While, in many ways, this is a good sign – hinting at recovery – a small proportion of people do not emerge from this phase. Smells appear inaccurate, dreadfully unpleasant or both. In my case, as I recovered, red wine tasted like kerosene and anything containing protein such as eggs and red meat tasted as though it had been overcooked to the point of being burnt. I was fortunate in that my distortions were relatively few. Other people find the process of simply breathing in the air around them unbearable, and food so disgusting their health suffers through poor nutrition.

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And life without taste and smell can be debilitating. Things you took for granted, say the smell of a bakery or coffee brewing, the outlandish pleasure of eating caviar and drinking champagne or something as mundane as a packet of crisps and a can of Coke, have vanished overnight, possibly never to return. Something as subtle as lettuce or something as powerful as chicken vindaloo, gone forever. It’s devastating but food cannot be avoided, you need it to survive, and the agony of mealtimes rolls around three times every single day. And so many social encounters involve food or drink. Sufferers have to sit in their bubble, cut off from the olfactory world while friends and family eulogise the food and drink on the table.

Yet few people seem to comprehend. It’s like inviting a deaf friend to a concert by the National Symphony Orchestra. And then, when you remember they can’t actually hear the soaring climax of Tchaikovsky’s 1812 Overture, suggesting that they at least watch the musicians waving bows and hitting cymbals.

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Naturally, when you lose what appears to be two of the only five senses you’ll ever have, you are prone to depression; the situation exacerbated by the fact that, to non-sufferers, it sounds quite trivial. Being told “well, at least you might lose weight” or “you’re lucky you can’t smell the leaky drain” is common, and deeply frustrating. And people with no sense of smell look outwardly “normal”. Some people cope well, but others become suicidal.

When the Australian INXS singer Michael Hutchence killed himself in 1997 he had previously cited his loss of taste and smell (in this case from a head in jury) as the cause of his depression. However, the coroner in Sydney refused to accept this as a contributory cause of suicide instead blaming it on the custody issues he was experiencing through his marriage to British TV presenter Paula Yates and his drug use. Only in later years has evidence from close friends and those who knew him, changed opinion. In 2019 the New Statesman published a story by Kate Mossman headlined “Michael Hutchence lost his sense of smell – and it all went downhill from there” saying that his injury “deprived him of the essence of his being”. Sufferers will empathise entirely.

Treatment options for viral anosmia are limited. First of all, there are other potential causes of a permanent loss of olfaction ranging from a head injury to inflamed nasal passages to a brain tumour (although tumours usually display a gradual onset of anosmia, rather than an instantaneous one) and these should obviously be ruled out first. But if the onset can be traced to a concurrent incidence of respiratory tract infection – either Covid-19 or any other form – this coincidence would normally lead to a likely diagnosis of viral anosmia. In many cases viral anosmia is a diagnosis made in the absence of other causes, so it is important check with a doctor.

Once diagnosed, the options are very few. Alternatives and quackery abound so beware. But because medical consensus says there is little, if anything, you can do, sufferers often resort to any remedy, however hopeless. I’m an atheist and even I rubbed holy water on my nose from a church font “just in case”. Ultimately I received treatment in the United States which, circumstantially at least, proved viable. One doesn’t take a baseline before anosmia strikes because we take our sense of smell – indeed all of our senses – for granted but I’m now, as far as I can tell, pretty much fully recovered.

So what’s the good news? Well I and many, many more have come through it. My recuperation was slow – probably four years from virus attack to full acuity – and progress was not linear. I experienced taste extinction – tasting the first mouthful of a meal and then not tasting subsequent bites. And smells would come and go, but eventually, given time, they persisted.

And, when you do fully emerge back into the world of olfaction, ecstasy awaits. You never take the smell or flavour of anything, however wonderful (newly mown grass, real ale and your spouse) or however dreadful (dog poo and week-old bananas) for granted again. All are equally welcome.