93 What canI doabout coldsores?

‘COLD sores are caused by a common herpes virus that cannot ever be eliminated,’ explains Roger Everett, a retired honorary professor, formerly of the Centre for Virus Research at the University of Glasgow. ‘People usually get infected at a young age, then the virus “hides” in their nerve cells.’

The sores occur when the virus ‘wakes up’, often as a result of stress (which weakens the immune system) or exposure to strong sunlight. Treat this active phase with over-the-counter creams containing the antiviral drug acyclovir (eg. Zovirax).

‘This should be applied to the sore frequently and as soon as any symptoms arise,’ says Professor Everett. This won’t completely stop a cold sore developing but will minimise it. In extreme cases, ‘such as if you have a damaged immune system, your GP may prescribe acyclovir tablets,’ says Professor Everett.

Another good over- thecounter option is cream containing penciclovir (sold as Fenistil and Vectavir).

Use it on the affected area four to five times daily for as long as instructed, adds Dr Michael Rudenko, a London- based consultant in allergy and immunology. ‘Also avoid touching the affected area during an outbreak so as not to spread the infection to others.’