Cold sores can be tiny and painful, and for some, they keep appearing over and over again.
Dr. Dick Zoutman, chief of staff at Scarborough Health Network in Toronto, says the virus that causes cold sores is known as herpes simplex virus type 1 (or HSV-1).
“Many people are infected with this virus but most have no symptoms at all. We spread the cold sore form of this disease through saliva and close personal contact to the saliva of others,” the infectious disease specialist explained.
“The herpes simplex virus attaches itself to nerve endings in the skin around the lips and mouth and then lives in those nerves. In fact, the virus then remains dormant in the nerves for the remainder of the infected person’s life.”
He says the virus periodically reactivates and can cause painful blisters on the lips that last about a week.
And because it sticks around in the nerve cells, cold sores can appear during times of stress, exposure to excessive sunlight or during a fever.
“Some people have only one episode of cold sores, but most people will have repeated attacks once or twice a year. Some very unlucky people might have attacks every month.”
The virus is very common
The appearance of a cold sore can feel slightly embarrassing, especially in social gatherings or work, but Zoutman says the infection is very common.
“They affect your appearance on your lips and face, which may lead to feeling self-conscious. If they recur frequently, they can be very distressing and a reason to seek the help of your doctor.”
Then there’s the herpes type 2 virus or HSV-2, says Dr. Sam Hanna, dermatologist and clinical director of Dermatology on Bloor in Toronto in a previous report with Global News.
“But there’s been a shift away from that with people being more adventurous about where they put their parts.”
READ MORE: Good chance you have herpes, says WHO
Herpes simplex virus type 1 is transmitted through mouth-to-mouth contact or oral secretions, Hanna said, while HSV-2 causes genital herpes via sexual contact.
While they used to be known as two separate viruses, health experts now say cold sores can cause genital herpes and vice versa.
Risk factors linked to cold sores
By the age of 50, Zoutman says between 50 per cent and 80 per cent of people have evidence of having antibodies to the virus in their blood.
“Some people have more recurrent episodes of cold sores than others and the reasons are not always obvious,” he said.
As mentioned before, sun exposure, stressful periods and fever have been linked to relapses of cold sores, but there are other factors, too.
“People whose immune systems are depressed due to cancer treatment with chemotherapy are particularly at risk and are often given medications to prevent recurrences of cold sores as these individuals can suffer very severe outbreaks of cold sores that go into the mouth and throat,” he said.
Unfortunately, there is no cure for cold sores.
“This is because the herpes simplex virus remains in the nerve cells and we have no way to get the virus out of the nerve cells.”
Hanna says in some cases, severe or very recurrent cold sores could leave little scars or pits in the skin.
“If someone gets them all the time, say six or more times a year, we’ll put them on a lower dose of an oral antiviral medication,” he said.
Zoutman says topical ointments and creams for cold sores are also common.
“They need to be applied every two to four hours during the day, making them difficult to use,” he said, adding their effectiveness can also be limited.
“If applied in the early stages of the outbreak of cold sores when you feel a tingling sensation telling you that an outbreak is about the start, these topical antiviral medication might reduce the duration of the outbreak by one day or so.
“Thus their impact is overall quite small.”
For more severe episodes of cold sores, or for patients with depressed immune systems due to cancer chemotherapy or other treatments that suppress the immune system significantly, doctors can prescribe oral antiviral pills, he said.
Examples of these drugs include acyclovir, famciclovir and valacyclovir.
“Because of cost and risk of adverse effects of the drugs they are normally only prescribed for severe cases of cold sore or for patients with immune suppression,” Zoutman said.
— with files from Global News’ Marilisa Racco