Last updated: October 20, 2026. The facts below reflect NHS guidance on cold sores. This guide is for general information only — it does not replace medical advice. If symptoms are severe or do not improve, seek medical help.

Cold Sores 2026: Symptoms, Treatment & Home Care Guide

That familiar tingle on the lip is back — and this autumn, it is everywhere. As the weather turns cold across the UK, searches for "cold sore" have climbed sharply, and pharmacists are seeing the usual seasonal wave: stress, tiredness, colds and dry, chilly air are waking the virus up. The good news: cold sores are manageable at home, and acting at the very first tingle makes a real difference. Here is what a cold sore is, how it develops, what actually helps, and when to see a GP.

What is a cold sore?

A cold sore is a cluster of small, fluid-filled blisters that appears on or around the lips. It is caused by the herpes simplex virus (HSV-1) — a very common virus that most people catch in childhood, usually through close skin-to-skin contact such as kissing someone who has a cold sore.

Once you have the virus, it stays in your body for life, quietly sitting in the nerves. Most of the time it does nothing. But when something weakens your defences — tiredness, stress, another illness, strong sunlight, or cold dry weather — the virus can wake up and travel back to the skin, and a cold sore appears. This is why cold sores keep coming back, and why autumn and winter are peak season in the UK.

Cold sore symptoms: the 4 stages

A cold sore follows a predictable pattern, usually over 7 to 10 days:

• Stage 1 — the tingle (day 1-2): Itching, burning or tingling around the lips. No blister yet — but this is the moment treatment works best.
• Stage 2 — blisters (day 2-3): Small fluid-filled blisters appear in a cluster on or near the lip.
• Stage 3 — bursting and crusting (day 3-4): The blisters burst and form a crusty scab. This is usually the most painful — and most contagious — stage.
• Stage 4 — healing (day 5-10): The scab shrinks, flakes away and the skin heals, normally without a scar.

What triggers a cold sore?

• Cold, dry autumn weather and chapped lips
• Stress, tiredness and lack of sleep
• Fever or another illness — cold sores were once called "fever blisters" for this reason
• Strong sunlight / UV on the lips
• A weakened immune system
• Hormonal changes, such as around periods

Cold sore treatment: what actually helps

There is no cure that removes the virus — but the right steps, taken early, shorten the outbreak and ease the pain:

• Antiviral cream at the first tingle. Creams containing aciclovir or penciclovir, started during the tingling stage, can shorten the outbreak by roughly a day. Your pharmacist can advise — for most cold sores, a pharmacist is the first stop, not the GP. Dab the cream on gently; do not rub it in.
• Paracetamol or ibuprofen for pain and swelling, as directed on the pack. (Never give aspirin to children under 16.)
• A cold compress — a clean, damp cold cloth held against the sore eases burning and softens crusts.
• Keep it clean, dry and protected. A plain lip balm or petroleum jelly stops the scab cracking; use one with SPF 15+ outdoors, since sunlight is a trigger.
• Drink plenty of fluids and avoid salty or acidic foods if they sting.

Stopping cold sores spreading

Cold sores are contagious from the first tingle until fully healed. Handwashing after any contact with the sore, keeping your own towel and cup, and avoiding close contact protect the rest of the household — especially babies, pregnant women, and anyone with a weakened immune system.

When to see a GP

• The cold sore has not started to heal within 10 days
• It is very large, very painful, or keeps coming back — a GP may prescribe antiviral tablets
• You or your child also have swollen, painful gums and sores inside the mouth
• You have a weakened immune system (for example from chemotherapy or diabetes)
• The patient is a newborn baby, or you are pregnant — get advice promptly

A note for carers and elderly patients

For most people a cold sore is a nuisance, not a danger. But in elderly patients and people with weakened immunity, outbreaks can be more severe, slower to heal, and a sign the body is run down. A trained home nurse can keep an eye on healing, help with hygiene routines that protect the rest of the family, manage pain relief on schedule, and spot early if a simple sore is turning into something that needs a doctor.