Cold sores

Last updated:

Reviewed by:

Dr Rhianna McClymont

, Lead GP at Livi

Medically reviewed

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

What are the 5 cold sore stages?

Stage 1: Tingling

A tingling feeling is usually the first indication that you have a cold sore coming on. As the cold sore virus HSV-1 travels along your nerves to your skin, it can cause a slight tingling, itching or irritation. This stage occurs on days 1 to 2 of catching the virus.

Stage 2: Blisters appear

On days 2 to 4, blisters will begin to appear on your lips, usually right where you felt the tingling. The blisters will be filled with fluid and usually red around the edges.

Stage 3: Blisters burst

The fluid-filled blisters tend to burst on day 4 or 5, leaving them open and sore. It's important not to not touch the blisters when they've burst as bacteria can get inside and trigger a secondary infection. Picking at the sores could also make them bigger.

If you do touch the blisters for any reason, wash your hands immediately to prevent the virus spreading to other parts of your body, or to other people. Be extra wary of face cloths and hand towels as these could easily come into contact with the open sore.

Stage 4: Crusting

A dry scab or crust will cover the sores on days 5 to 8 – this is the healing process. These scabs can crack and split which can be very painful. Again, it's important not to pick at this point as it will slow down the healing process.

Stage 5: Scabs peel off

At some point around days 8 to 10, the scabs will start to flake off on their own, and the skin underneath will usually be slightly red. This red skin can linger for a few more days as your skin fully heals. The blisters can still be contagious at this point, so if you have to touch them for any reason, remember to wash your hands.

How to get rid of 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

Cold sore vs pimple on lip – what's the difference?

The key differences between cold sores and pimples include:

  • Cold sores cause a tingling or burning sensation before they're visible, whereas pimples usually appear without warning.

  • Cold sores are typically more painful. Although pimples can feel uncomfortable, they do not usually hurt unless they've been picked or become large or swollen.

  • Cold sores will look more like blisters after a few days. Pimples typically develop a white or black head.

  • Cold sores can last for 2 to 3 weeks. Although large or swollen pimples can last for several weeks, smaller pimples often clear up within a few days.

See a GP about a cold sore 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

Last updated:
Reviewed by:
Dr Rhianna McClymont, Lead GP at Livi