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Cold Sores

Herpes Labialis (Latin name)

By Bjarne Lühr Hansen PhD, MD and Philipp Skafte-Holm MD, Mentor Institute

Cold sores are a contagious disease caused by infection with a virus (herpes simplex). The disease turns out like sore blisters and later sores on the lips. The disease comes repeatedly - often with a strong cold. Call the doctor immediately if the wounds spread to the nose or eyes.

Cold sores are a contagious disease caused by infection with a virus (herpes simplex). About one third of the adults have had cold sores at one time or another in their lives.

Often the disease begins with redness and an uncomfortable tingling or stinging of the skin at the place where the bladders later emerge. After a few days, small fluid-filled blisters develop which quickly break and become sore. The wounds are covered by a crust that usually falls off after 8 to 10 days.

The bladders and wounds sit on the lips and sometimes also in the mouth. In rare cases, herpes simplex can attack the eye, which becomes red and painful. 

The worst thing about cold sores is that the wounds tend to come repeatedly. If you have had an outbreak of cold sores, there will always be a risk of the wounds coming back. Typically, the wounds occur in the case of colds (hence the name of cold sores) or other infection. Also, sunlight can cause the wounds to come again. Every fifth will have repeated outbursts of cold sores throughout life.


Most people get infected by healthy infectious carriers, e.g. people who have viruses but do not sore or blow. It is therefore difficult to completely avoid spreading the disease.

Wash your hands frequently when you have an outbreak and always after touching your bladder or wounds.


There are medicines that shorten the time the disease lasts, but completely eradicating the virus, the medicine can not. In case of single bladders or sores, they are treated with zinc ointment. In case of major outbreaks or frequent repeated outbreaks, treatment with virus-killable creams or tablets may be discussed.


What can you do?

Cold sores can develop when the lips are exposed to sunlight. If you have previously had cold sores, you can use lip balm with a high solar factor when your face is exposed to strong sun..

It is important that treatment begins as early as possible. If you have had an outbreak of cold sores, it is advisable to have antiviral medicine at home, so treatment - at a new outbreak - can begin immediately.

Avoid touching the cold sore - it can spread the disease and it can lead to inflammation. 

Beware of infection. Wash hands after touching the wounds.


Contact the doctor tomorrow

At the first outbreak of cold sores. If the wounds are not healed within 2 weeks. If there is thick fluid from the wounds. If the wounds occur very frequently.


Contact the doctor immediately

If the wounds spread to the nose or eyes. If your eye turns red.