Cold Sores

VirusHerpes Simplex VirusPrimary oral infection with the virus responsible for cold sores (herpes simplex virus (HSV)) typically occurs at a young age and is asymptomatic. Some children develop a  symptomatic primary infection, presenting with inflammation and ulceration of the mouth and gums. The skin around the mouth may be affected and there may be swollen lymph glands, high temperature and loss of appetite. After the primary oral infection, HSV may remain inactive only to be activated later as the more common herpes labialis, or “cold sores”. Triggers for reactivation are well known and include sunlight, trauma, tiredness, stress, and menstruation. An episode of “cold sores” usually begins with a burning sensation on the affected area of the lips, which is usually followed by the development of painful blisters. The appearance of “cold sores” is a well-localised cluster of small vesicles along the red border of the lip or adjacent skin. The vesicles rupture, ulcerate, and crust within one to two days and heal within seven to 10 days.

Cold sores are contagious and strict hygiene measures should be adopted when a person is infected.


Prevention is difficult, although the use of sun barrier creams will help reduce attacks in those holidaying in the sun. Also, a well-established product on the market (containing 5% w/w acyclovir), if applied during the early burning phase of cold sores, has been shown to be effective in reducing the duration of the episode.