Frequently Asked Questions

Cold Sore Causes

How do you catch a cold sore?

A cold sore is caused by the Herpes Simplex Virus type I. Most adults have been exposed to the virus, with initial infection usually occurring in childhood, probably after sharing a drink or being kissed by a person with the infection. The cold sore virus is reactivated in only about a third of adults, and usually by every day factors such as ultraviolet light or cold and flu.

Can I get a cold sore from having sex?

Cross-infection of HSV-1 (cold sore virus) and HSV-2 (genital herpes virus) may occur during oral sex. You should avoid having oral sex whilst you have a cold sore.

You should also avoid kissing anyone when you are suffering from a cold sore as it is one of the more common ways of spreading the cold sore virus.

What is the most common age group to suffer from cold sores?

Cold sores affect all age groups. The vast majority of individuals suffer their first attack in childhood.

What are the main triggers of cold sores?

  • Immune system is under stress
  • Ultraviolet light
  • Common cold, flu or feverish illness
  • Emotional stress or exhaustion
  • Exposure to extreme temperatures or weather conditions
  • Feeling physically low or fatigued
  • Pregnancy
  • Menstruation
  • A knock on the lips or face
  • An injury to the mouth, surgical operation or dental treatment.

Read more on this

How often will I get a cold sore?

Cold Sore attacks vary. Some people get them very infrequently, like once every few years. Others may get them once a month. Those who experience very frequent or severe attacks or have sores away from the mouth area should seek the advice of a doctor.

What can I do to prevent getting a cold sore?

Eat a balanced diet and be aware of your triggers.

Cold Sore Cures

Can I be cured of cold sores?

There is no cure for the condition, which fortunately in most people is just a short-lived nuisance that can be treated with the help of antiviral products available in supermarkets or pharmacies. If you are experiencing frequent or severe episodes of cold sores, then you should seek the advice of a doctor.

What are the main treatment options for cold sore?

Because cold sores are caused by a virus, the most effective treatments contain an ingredient active against this virus. The antiviral agent, aciclovir, contained in Zovirax Cold Sore Cream, reduces the replication of the virus to help speed up the healing process. Zovirax also offers invisiSeal patches which are useful to prevent contamination and spreading. They also create a germ-free environment to promote healing.

If I miss the early tingling feeling of a cold sore attack, can I still treat my cold sore?

The earlier you start treatment the better but treatment with an antiviral cream, such as Zovirax Cold Sore Cream, is still effective if applied at the blister stage of the cold sore. See our How to treat section

Can I ever get rid of the cold sore virus?

No. Once you have been infected by the virus, it resides indefinitely in the nerves that supply sensation to your lips and surrounding skin. It may, however, be possible to avoid triggers that set it off and take action to improve the body's natural defences. See our Triggers section

How long is a cold sore attack likely to last?

Untreated, cold sores usually last for around 10 days.

Is there a vaccine against cold sores?


Lifestyle and Cold Sores

Is what I eat important in stopping cold sore?

There is no clear scientific evidence in this area. Certainly a healthy balanced diet helps to keep you healthy. Such dietary advice would be good for anyone whether or not he or she has cold sores.

Will my cold sores disappear as I get older?

Cold sores affect all age groups but many people find that with time they have fewer attacks.

Can I give a cold sore to my friends?

You shouldn't share drinks or kiss anyone when a cold sore is present, as these are some of the most common ways of spreading the cold sore virus since it is carried in saliva, as well as in the blister fluid.

Can I still have a sex when I've got a cold sore?

You shouldn't kiss anyone when you are suffering from a cold sore as it is one of the more common ways of spreading the cold sore virus since it is carried in saliva, as well as in the blister fluid. Nor should you participate in oral sex as you can pass the cold sore onto someone's genitals as genital herpes.

Can I swim with a cold sore?

There is no reason why you cannot go swimming when you have a cold sore. You cannot pass the infection on to someone else through pool water.

Cold Sore Myths

Only dirty people get cold sores

Anyone can get cold sores. Most people have been infected with the virus at some time in their lives. Fortunately, only a small proportion of these people have trouble with cold sores. There is no clear explanation for why some people live with the virus and never get cold sores and others experience recurrent outbreaks.

You get one after you've had a cold

Some people notice that cold sores often break out when they are run down with a cold or flu. However, the cold may simply be the trigger for the cold sore outbreak. The virus that causes cold sores is taking advantage of the fact that the body's natural defences are run down.