Cold Sores

What are cold sores?

Cold sores are blisters on the lips or mouth, caused by the herpes virus, which are typically recurring over the long term. Symptoms usually start with a tingling sensation before a blister begins to appear and remains for around 7 to 10 days. This can be accompanied by other symptoms such as a fever.

What causes cold sores?

Cold sores are caused by the herpes virus which is extremely contagious. Once infected, there may not be immediate symptoms as the virus remains inactive until it is triggered by factors such as the flu, fatigue or stress.

Who is at risk of developing cold sores?

The herpes virus can be contracted by kissing someone with a cold sore blister, sharing towels, cosmetics or cups with someone who has a cold sore, or have sexual intercourse with a person carrying the simplex virus i.e. genital herpes.

Treatment of cold sores

Cold sores cannot be cured as the virus remains underlying and therefore they can reappear in the future whenever triggered.

Cold sores can be treated using Aciclovir cream or tablets to prevent the infection spreading further and help the blister to heal. Treatment should begin immediately after symptoms start, even before the blister is visible.

Aciclovir cream should be applied directly to the blister once every 4 hours for 5 days.
Aciclovir tablets (200mg) are usually taken once every 4 hours, 5 times a day for 5 days.

Side effects for cold sore treatments

Common side effects of Aciclovir cream include mild drying or flaking of the skin. It can rarely cause itching, erythema or hypersensitivity reactions.

Aciclovir tablets can commonly cause headache, dizziness, nausea, diarrhoea or stomach pain. They may also, more rarely, produce more serious side effects including hives, hair loss, liver inflammation and jaundice. Seek medical advice if you are pregnant or breastfeeding before taking this medication.

Side effects for cold sore treatments

Common side effects of Aciclovir cream include mild drying or flaking of the skin. It can rarely cause itching, erythema or hypersensitivity reactions.

Aciclovir tablets can commonly cause headache, dizziness, nausea, diarrhoea or stomach pain. They may also, more rarely, produce more serious side effects including hives, hair loss, liver inflammation and jaundice. Seek medical advice if you are pregnant or breastfeeding before taking this medication.