Most people are familiar with cold sores, the small blisters or scabs that develop on the lips. Cold sores are caused by the herpes simplex virus and occur after an outbreak when virus levels build up. Cold sores will often start in the ‘tingle’ phase where there is a tingling, itching or burning sensation in the area before a breakout where the blisters occur. The blisters or sores usually last for around 7 to 10 days and will clear up without treatment. If you start treatment at the tingle stage, you can sometimes prevent the outbreak from happening.
Cold sores are caused by one of the herpes simplex virus family known as HSV-1. In rare cases cold sores can be caused by HSV-2, however this is normally due to having oral sex with a person who has genital herpes.
Cold sores are highly contagious and are passed on by direct contact, normally through kissing or sharing lipsticks or cutlery. Once you have HSV-1, it lies dormant in the nerves until an outbreak, normally caused by a trigger factor. Some people can get outbreaks every few months whereas others can go for years without a cold sore.
Cold sores occur when levels of the herpes simplex virus build up causing an outbreak of small blisters on the lips. The outbreak of cold sores is usually caused in response to trigger factors that can include:
- A low immune system (possibly due to another infection or illness)
- Fever or high temperature
- Stress or being upset
- Tiredness or fatigue
- Exposure to strong sunlight
- Injury to the mouth or lips
Although an outbreak normally occurs in response to a trigger factor, cold sores can also occur randomly where there is no obvious trigger.