Cold Sores

Cold Sores

Cold sores are unsightly, painful fluid-filled blisters that form on or around the lips. They are caused by a herpes virus - usually ‘herpes simplex 1 viruses and are contagious.


  • Tingling, itching, burning sensation around mouth
  • Outbreak of small blisters that weep clear fluid
  • After a few days blisters break, ooze and crust over.

What causes cold sores?

The virus is usually caught early - often in childhood, when an infected person kisses the child. The virus travels through the skin and lays dormant until it’s triggered at a later date by an event such as stress, tiredness or menstruation.

Occasionally a cold sore is contracted after having oral sex with a person who has genital herpes (caused by herpes simplex virus type 2).

How are cold sores treated?

After a few days the blisters break, ooze, and crust over before healing. They usually clear up within 7-10 days without leaving scars. You may need painkillers if the cold sore is particularly painful and you should consult a doctor if the sore lasts longer than a fortnight despite treatment or if your eyes become sore. Eye infections need immediate treatment to avoid damaging your sight.


  • Avoid the triggers that you know bring-on cold sores. If sun is to blame use a lip balm containing a sun block.
  • Use a simple over-the-counter cold sore treatment containing the antiviral agents aciclovir or penciclovir. These can be used even during the tingling stage which may stop the blister from appearing in the first place. Even if the blister does break-out the treatment can shorten its duration.
  • Wash your hands thoroughly to avoid transmitting the virus.
  • Eat healthily to boost your immune system as you’ll be more vulnerable to cold sores if you’re feeling run down.


  • Pick, scratch or touch the cold sore. You’ll risk transferring the infection to your eyes (particularly if you need to insert contact lenses).
  • Unfortunately cold sores often reoccur - triggered by stress, sun exposure, illness or sometimes during menstruation.