But another odd symptom seems to be a calling card: a sudden loss of smell. The symptom appears to be common even though it is not yet widely acknowledged. More than two-thirds of those with coronavirus in Germany report losing their sense of smell, and 30% of sufferers in South Korea had anosmia as their main symptom, according to a report from ENT UK, an organisation that represents ear, nose and throat surgeons.
The smell loss associated with coronavirus is different to that which you might get with a normal cold, says Prof Claire Hopkins, president of the British Rhinological Society.
“Typically when you have a cold your nose is congested and no one is surprised you can’t smell,” she says. “But what’s happening here is there is no nasal obstruction, so people are surprised.”
“We have seen evidence showing how the virus has the ability to affect the nerves, and the smell nerves are the only bits that are exposed in a way that no other nerves are,” says Carl Philpott, professor of rhinology at the UK’s University of East Anglia.
He believes the virus causes neuronitis or inflammation of the nerves in the nose, which stops them performing as they should. Doing further research at present is difficult, says Philpott.
“We would need to examine the noses, and that’s what we’re telling people not to do as it puts the doctor at massive risk.”
Worryingly, anosmia can appear entirely by itself and without the “typical” coronavirus symptoms, which means many will not be aware they have it. This seems to be fairly common: in a study of suspected coronavirus sufferers with smell loss, one in six had it as the only symptom, according to Hopkins. A further one in 10 lost their sense of smell before getting other symptoms, which shows they could be spreading infection before reaching the criteria that require self-isolation.
Anosmia appearing without other symptoms is something we should be aware of, says Prof Nirmal Kumar, president of ENT UK.
“The spreading of it is difficult because these patients aren’t terribly unwell, so they are walking around as if nothing is wrong,” he says.
This seems to be particularly the case with younger people: “I saw nine young people with loss of sense of smell who were otherwise fit and well this month. That’s extremely unusual, I might usually see one a month,” says Hopkins.
Some patients who are reporting smell loss are also saying they have lost their ability to taste. The likelihood is they are mistaking smell for taste, says Philpott. “When you’re eating, 80% of what you appreciate of flavour is the smell, so people think they can’t taste even though they can still get salty, sweet, bitter and sour.”
Some patients are experiencing dysgeusia: things tasting different to normal. Most people suffering this are describing a “metallic taste”, says Hopkins.
The good news is that the coronavirus-induced anosmia looks as if it will be temporary; most patients who have reported it describe their sense of smell returning within a fortnight.
It could be that smell loss is not the only symptom of coronavirus that’s not being picked up.
Two people who suffered loss of smell
‘I burnt dinner twice without realising’
March 16 was just another day in the office, a week later, the country was in lockdown and my cold-like symptoms had become a preoccupation. Then came Wednesday and something particularly strange. I had ordered a bottle of eucalyptus oil to be delivered. When it arrived, I almost sent it back as defective — it had no smell.
Next stop was the kitchen, where I first tried smelling coffee, then vinegar, followed by minced garlic. That’s when the penny dropped; I had no sense of smell. It hadn’t happened gradually, it had gone all at once and in its entirety. At this point, loss of smell had not been announced as a coronavirus indicator, so it was more puzzling than worrying, especially as I wasn’t feeling ill.
By Friday, it was added to the list of reported symptoms, I had lost my sense of taste, too, and with that my appetite — nothing really seems worth the effort at the moment. At the weekend, I burnt dinner twice, but didn’t realise until the smoke alarms went off.
I don’t have the telltale symptoms of fever or dry cough, but I do have a chesty cough, slight breathlessness, aches in my neck and lower back, and a headache. Fully aware of how rapidly the virus spreads, I have self-isolated as I don’t want to risk transmitting anything. — Tracey Llewellyn
‘My senses of smell vanished, but I didn’t have a cough or fever’
Like millions of others across the UK, I spent last Monday evening with my dinner on my lap, watching [British prime minister] Boris Johnson’s address to the nation. One half of my mind was focused on Johnson, as he announced sweeping changes to our way of life. But the other half was focused on my beef stroganoff, which tasted remarkably bland.
After sniffing a strong-smelling bottle of gin, as well as a particularly pungent jar of mustard, I discovered that my senses of smell and taste had vanished. Anosmia, I discovered after some online research, might be an early symptom of coronavirus. I opened my laptop to fill in the NHS’s online diagnostic test, with the view to getting a blood test. But after answering just five questions I was told it was “unlikely” to be coronavirus because I didn’t have a cough or a fever.
Other unusual symptoms?
Red eyes: The World Health Organisation (WHO) said 0.8% of patients studied in China had conjunctivitis. A carer in Washington state said in her nursing home the “most important” sign of Covid-19 was red eyes.
Leg spasms: A UK Daily Telegraph writer who self-isolated with a cough and fever reported that her legs spasmed in the early stages.
Pain in joints: In the WHO report, 14.8% of Chinese patients studied reported pain in their joints or muscles.
Coughing up blood: A 28-year-old man who contracted the virus, but was otherwise well, told television programme Good Morning Britain he had coughed up blood. This happened in 0.9% of Chinese cases studied.
Stomach upsets: In the WHO study, 5% of patients experienced nausea or vomiting and 3.7% had diarrhoea.
— Telegraph Media Group Limited (2020)