Almost every day, new information is discovered about the deadly and elusive novel coronavirus.
One aspect of COVID-19 that continues to perplex medical researchers is the wide variety of symptoms that people with the virus can develop.
When the pandemic first began, Canadian public health authorities said the major symptoms of COVID-19 were a cough, fever and difficulty breathing.
READ MORE: Why does the coronavirus seem to cause so many different symptoms?
Since then, a long list of peculiar — yet relatively common — symptoms have joined the list.
In April, the Centre for Disease Control and Prevention (CDC) in the United States added six more symptoms to its official list after they repeatedly appeared in people with the virus:
- Loss of taste or smell
- Chills
- Shaking with chills
- Muscle pain or aches
- Sore throat
- Headache
This week, the CDC added three more:
- Nausea
- Diarrhea
- Runny nose
However, there have been reports of other peculiar symptoms, including patients with signs of unusual blood clots, lesions and rare inflammatory diseases in pediatric patients.
Dermatologists around the world are keeping an eye out for possible skin symptoms after reports that the disease can cause lesions as part of something known as “COVID toes” or “COVID hands.”
“They’re these painful red and purple bumps that tend to occur at the tips of the toes or on the tops of the feet, or on the tops of the fingers or tips of the fingers,” Dr. Kerri Purdy, president of the Canadian Dermatology Association, previously told Global News.
Other kinds of rashes have been reported in COVID-19 patients too, she said, but it’s too early yet to know how common skin symptoms are with the disease.
READ MORE: Severe COVID-19 patients have ‘unprecedented’ blood clots. Here’s what doctors know
And although the virus is rare in children, when it does happen, the symptoms appear to be completely different.
At least 285 U.S. children have developed a serious inflammatory condition linked to the coronavirus and while most recovered, the potential for long-term or permanent damage is unknown, two new studies suggest.
The papers, published online Monday in the New England Journal of Medicine, provide the fullest report yet on the condition.
The condition is known as multi-system inflammatory syndrome in children. It is considered uncommon and deaths are rare; six children died among the 285 in the new studies.
Digestive symptoms including nausea and diarrhea are common. Some children may have symptoms resembling Kawasaki disease, a rare condition in children that can cause swelling and heart problems.
So how does a single virus cause so many symptoms?
One possible explanation: it doesn’t.
READ MORE: What is ‘silent hypoxia’? The coronavirus symptom patients don’t know they have
Dr. Gerald Evans, chair of the division of infectious diseases at Queen’s University, suggests that many of the symptoms currently being ascribed to COVID-19 are already present at similar levels in the general population, or are the effects of any severe infection — not just infections from the novel coronavirus.
For example, conjunctivitis is present in about 0.8 per cent of COVID-19 cases according to one study.
“So the interesting thing is, if you look at what is the incidence of conjunctivitis in the general population, it’s 0.8 per cent. So I think it encapsulates the problem that you have,” he previously told Global News.
READ MORE: New coronavirus symptoms include headaches, loss of taste and smell
Another possible explanation, according to Jason Kindrachuk, who holds the Canada Research Chair in Emerging Viruses at the University of Manitoba, is that we’re noticing more cases of very rare symptoms — simply because the numbers are so high.
He saw a similar effect when studying Ebola, he said. Early on, when there were relatively few cases, doctors thought they had a good idea of what the disease looked like.
But in the 2014 outbreak in West Africa, so many people were infected that doctors got a much better idea of all the possible effects of Ebola.
“2014 hits and we have tens of thousands of cases. And now you start to get a little bit more of an indication of the nuances of what the disease actually looks like,” he previously told Global News.
“It doesn’t maybe fit the blueprint that we had, because now we’re actually seeing this across a much broader number of patients with very variable stages of disease. You’re not seeing just the people that are ultra-sick, you’re seeing people that maybe are more mildly sick.”
Similarly, with all these millions of COVID-19 cases, he doesn’t think we’re seeing new disorders cropping up, but instead the relatively rare effects that only occur in a handful of people.
Questions about COVID-19? Here are some things you need to know:
Symptoms can include but are not limited to: fever, cough and difficulty breathing — very similar to a cold or flu. Some people can develop a more severe illness. People most at risk of this include older adults and people with severe chronic medical conditions like heart, lung or kidney disease. If you develop symptoms, contact public health authorities.
To prevent the virus from spreading, experts recommend frequent handwashing and coughing into your sleeve. They also recommend minimizing contact with others, staying home as much as possible and maintaining a distance of two metres from other people if you go out.
In situations where you can’t keep a safe distance from others, public health officials recommend the use of a non-medical face mask or covering to prevent spreading the respiratory droplets that can carry the virus.
For full COVID-19 coverage from Global News, click here.
— With files from Global News’ Leslie Young & the Associated Press