Cold sores

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Cold sores, also called fever blisters or lip herpes, are the symptom of infection with a virus belonging to the family of the herpes viruses. Many people often suffer from these cold sores several times a year. In some cases, their onset is indicated several hours before they occur by mild burning, tension or tingling in the relevant area.


Most people come into contact with herpes viruses over the course of their lives. The first infection usually occurs during childhood and goes unnoticed, often before the age of six. Infection can occur via direct contact with the fluid in the blister or the saliva of someone infected with lip herpes, but also via droplets (speech, sneezing, coughing) and infected objects such as napkins, glasses or cutlery. The viruses enter the body through small injuries to the skin or mucous membranes, replicate in cells in the upper layers of the skin and thereby cause the known cold sores. Some of the viruses migrate along nerve fibres to the ganglia, a group of nerve cells. They can then no longer be attacked by the immune system. The viruses can therefore persist in a latent condition in the ganglia over many years. The viruses are reactivated in specific circumstances, migrate back along the nerve fibres to the surface of the skin, where they again produce cold sores.

The trigger for this reactivation can be a weakening of the immune system, e.g. due to an infectious disease or fever, exposure to strong sunlight (skiing in the winter) or other skin irritation due to psychological stress factors, or also in association with hormonal change in women (pregnancy, menstruation). The incidence of cold sores can also be favoured by taking medicinal products that suppress the immune system.

Options for treatment

There are several options for treating cold sores. Common to all of these options is the necessity of using them as early as possible, as soon as the first symptoms are felt. There are now a variety of creams and gels available, in addition to tablets that must be prescribed by a doctor.