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Cold sores

Cold sores are painful blisters on the face caused by a virus. Learn more about the causes, symptoms and what you can do.

What is a cold sore?

A cold sore is a small collection of blisters that usually appears on the face - specifically around the lips. It’s caused by the herpes simplex virus.

Cold sores are contagious from when the first symptoms appear, to after the lesion has completely resolved.

Cold sore symptoms may not appear immediately after infection, and the first eruption of a cold sore may be quite some time later. Once you're infected, the virus remains in the body and can cause further eruptions of cold sores.

What causes cold sores?

Cold sore eruptions can be random, but they’re also often triggered by certain factors such as:

  • Fatigue

  • Stress

  • Strong sunlight

  • Other illnesses and infections

  • Trauma to a certain part of the face

  • Menstrual periods

Cold sore symptoms

Cold sores are particularly common around the edges of the lips, but can occur anywhere on the face. Symptoms of cold sores typically appear in the order below.

  • A tingling, itching or burning sensation

  • Followed by small, fluid-filled blisters

  • Followed by crusting as these blisters burst

How to treat a cold sore

Cold sores usually get better on their own within 7-10 days.

If applied early (as soon as the first symptoms of tingling start), antiviral creams, bought from a pharmacy, can be effective. These should be applied to the area affected by the cold sore.

For more severe cold sore cases, or for people who develop recurrent episodes of cold sores, antiviral tablets can be prescribed by a GP. To be effective, these need to be taken as soon as symptoms first appear.

Here are some simple cold sore remedies:

  • Avoid touching a cold sore (unless applying cream)

  • Dab cream on, rather than rubbing it in

  • Avoid the possible trigger factors mentioned above

  • Use paracetamol or ibuprofen for pain if needed

  • Avoid acidic and salty foods – as these may aggravate the cold sore and cause discomfort

To prevent spreading the infection to others:

  • Wash your hands after applying any cold sore cream or touching your cold sore

  • Don’t share anything that touches your face, like towels, cutlery, food, makeup or cold sore cream with anyone else

  • Avoid kissing and oral sex until the cold sore has completely healed

See a GP if...

  • You’re in a lot of discomfort, or the cold sore is stopping you from eating and drinking

  • The cold sore has spread or developed close to your eye

  • You’ve not seen any improvement in the cold sore after 10 days

  • You have inflamed and painful gums

  • You have a weakened immune system or you're being given chemotherapy

Reviewed by:

Dr Rhianna McClymont

Lead GP at Livi

Last updated: