Why COVID headaches can be hard to shake — and when you should worry

For some people with COVID-19, the pain in their skull is so intense they consider a trip to the emergency room. 

For others, it might come in throbbing waves or feel like a constant mild ache; it could be gone within minutes of taking painkillers or still be there months later.

"My head felt like it would explode, and no medication was enough to make it better," said Ananda Pires, who fell ill in late December.

After two days during which she was barely able to move from her bed, the Guelph, Ont., woman said her headache mostly disappeared, with just minor pain and sensitivity to light in the days that followed.

While loss of smell, fever and dry cough may be more publicized symptoms of COVID-19, headache is a common one, too. And, two years into the pandemic, patients and physicians are beginning to recognize that, for some, it may be by far the worst symptom — and one that lingers after others are gone.

It's why there's been a push by researchers, including the U.S. National Institutes of Health, to study the little-understood long-term neurological symptoms reported in some acute COVID-19 patients, which can include headaches, brain inflammation and damage to brain blood vessels.  

While some people's headaches disappear alongside the illness, other patients can't seem to shake them — even long after their other COVID symptoms are gone. 

Dr. Nili Kaplan-Myrth tested positive for COVID at the start of April. The Ottawa family physician is now well enough to resume seeing patients, but she still has an incessant headache that she describes as "like a vice."

"It's like you're wearing a hat that's too small," Kaplan-Myrth told CBC News. "It's a dull pain that's just always there."

For Scott Schmidt, the COVID headache "was like living under water for a few weeks," with a constant pressure behind his eyes.

"I was like, I just cannot shake this headache for the life of me. I became used to it. I honestly just started going about my day with a headache," Schmidt, a journalist from Medicine Hat, Alta., said.

Headaches are common to viral infections, including colds and flu. They are often one of the earliest symptoms of COVID-19, which, physicians have noticed, can make it difficult to distinguish whether it's just a headache — or a sign of a developing illness.

Dr. Sumon Chakrabarti, an infectious disease specialist in Mississauga, Ont., says he's seen patients present at emergency rooms with a severe headache and then test positive for COVID. 

But others might brush off a minor headache and not realize they're infected.