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Cold sores - The facts on herpes labialis

Published on October 21, 2014 at 14:42 / Updated on September 26, 2019 at 18:45

Herpes labialis (commonly known as cold sores) occurs when a person contracts the type 1 herpes simplex virus (HSV-1), or more rarely the type 2 form.


Herpes labialis (commonly known as cold sores) occurs when a person contracts the type 1 herpes simplex virus (HSV-1), or more rarely the type 2 form (HSV-2, which usually causes genital herpes). The initial infection with this virus may manifest as a cold sore or go unnoticed and cause no visible lesion. The individual may also experience some discomfort or have a fever. Following the first infection, the virus settles into a nerve ending, where it remains in a dormant state. It is estimated that nearly 90 percent of the population will be in contact with the herpes simplex virus at some time in their life. However, most people develop antibodies against the virus, which prevents it from causing new eruptions. Approximately one-third of individuals affected present with lifelong repeated symptoms. While cold sores are uncomfortable, they do not have any significant health consequences, except in persons with a compromised immune system.

Certain conditions are favourable to the virus being activated and causing cold sores. Common factors that can trigger cold sores include fever, the flu, prolonged exposure to the sun or to extreme temperatures (heat or cold), stress, anxiety, fatigue, allergies and menstruation. Individuals who regularly suffer from cold sores eventually learn to identify the factors that trigger them and can therefore take measures to avoid them.


Herpes labialis is especially contagious when there is an eruption, but studies suggest that 70 percent of people contract the virus when the infected individual shows no symptoms. In those cases, the virus appears to be transmitted through microscopic skin lesions.

Cold sores remain contagious until they are completely dried up. The virus is transmitted mainly through direct contact with the blisters, indirectly through contaminated objects (utensils, towels, etc.), or through saliva. In adults, kissing and oral/genital sexual contact are thought to be the leading means of transmission.

While cold sores generally appear on the edge of the lips, they can spread to other areas of the face (cheeks, ears, nose) and of the body. Particular care must be taken with the eyes, as an eye infection with the herpes simplex virus can be very serious.

When you scratch a cold sore, you risk spreading the infection to other parts of the face. Scratching also means the virus can get lodged under your nails and then be carried to other areas favourable to its development, like the genitals. In addition, excessively scratching a cold sore can allow other skin bacteria to develop and thus cause a secondary infection. It is therefore important to wash your hands frequently and to keep your nails short when you have cold sore symptoms. It is also important not to touch a seeping cold sore directly.

Whenever possible, individuals with active herpes labialis must avoid any contact with persons whose immune system is compromised (individuals with HIV/AIDS, the elderly, infants, persons undergoing chemotherapy or immunosuppressive therapy). Since these groups have weakened immune defences, a herpes simplex infection could prove much more serious for them.


There is currently no treatment to get rid of the virus that causes cold sores. However, infected individuals can take certain measures to prevent the onset of lesions or at least reduce the intensity of their symptoms.

The first measure is to avoid factors that can precipitate a herpes outbreak, whenever possible. For example, you should apply lip balm with an SPF 15 sunblock anytime you are exposed to the sun.

Having a strong immune system is also thought to prevent recurrences. A healthy lifestyle, which includes a healthy diet, sufficient sleep and regular exercise, will help you maintain good overall health and decrease your risk of developing new eruptions.


Some people experience prodromal symptoms in the 12 to 24 hours preceding a cold sore eruption. These warning signs usually manifest as a burning sensation, itching and prickling on the edge of the lips. Taking antiviral tablets as soon as these warning symptoms appear helps prevent a herpes outbreak or at least reduce its severity. These drugs must be prescribed by a physician. Since they are most effective when taken in the hours preceding a cold sore eruption, it is best to always keep a dose of this antiviral medication on hand.

Once the lesion has appeared, no treatment can quickly cure it. There are only small measures designed to alleviate the discomfort, itching and pain that come with it. An episode usually lasts seven to ten days.

You can apply cold compresses to seeping lesions to help reduce the pain. It is important not to burst the blisters in order to prevent the cold sore from spreading or leaving a scar once it heals. Once all the blisters have dried up, you can apply a moisturizing cream or an ointment (e.g. Vaseline) to stop the crusty surface from cracking. Don’t apply any cream to a blister that is still seeping, as this could spread the cold sore to the rest of your face. Always avoid cortisone-based creams, which promote herpes infections by diminishing the immune response.

If the pain becomes too great and there are no contraindications, you can take an analgesic such as acetaminophen or ibuprophen, unless contra-indicated. Various creams available either over-the-counter (e.g. Lipactin®) or by prescription (Zovirax®) are not usually very effective. If they are applied at the very onset of symptoms, they may slightly reduce the healing time, but they only mildly alleviate the discomfort caused by cold sores.

You should see a doctor if the lesions do not heal within two weeks, if the episode is accompanied by fever or very intense symptoms, if cold sores recur frequently or if your eyes become sensitive to light during or after an episode, which could indicate that the infection has spread to the eyes.


Herpes labialis is a contagious and incurable viral infection, but it is usually benign. It can be prevented by avoiding any direct or indirect contact with an infected person’s cold sore. If you have recurrent episodes, you can take certain measures to prevent cold sore eruptions, for example learning to identify and avoid precipitating factors. Unfortunately, there is no effective treatment against cold sores; we can only alleviate the discomfort they cause.

Speak to your pharmacist or physician for more information of herpes labialis and its treatment.

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