Cold Sores

A cold sore is a sore or blister that develops on the lips or around the mouth. They are caused by the herpes simplex virus. 

Cold sores normally clear up on their own within 7 to 10 days, but you can treat symptoms like itching, burning and pain and speed up healing with antiviral creams like aciclovir (Zovirax). 

Cold sores are highly contagious from when you first feel a cold sore developing until it has completely healed.

Cold sores are a common infection caused by a type of virus called the herpes simplex virus. 

It is normally caused by the herpes simplex type 1 virus ( HSV-1) but may also be caused by the herpes simplex type 2 virus (HSV-2), the virus responsible for genital herpes. This is normally caused by having oral sex with someone who has genital herpes. 

Many people carry the herpes simplex virus and are unaware that they have it. Most people don’t develop symptoms when they are first infected with the virus, and some people never get symptoms. 

The herpes simplex virus can lie dormant in your body for many months or years before a cold sore appears. They are more likely to appear when you are run down, such as when you are tired or unwell, though sometimes there is no obvious trigger. 

There is currently no cure for cold sores, and once you have the virus, they may come back periodically throughout your life. 

Some things that may trigger a cold sore include: 

• tiredness and fatigue 
• infection
• injury to the lips or mouth
• having your period
• strong sunlight
• having a fever 
• stress

Cold sores are spread from one person to another by close contact such as kissing and sharing items like drinking straws, cups, and utensils. 

The first sign of a cold sore is usually a burning or tingling sensation around the mouth and lips before redness appears. This is followed within about 48 hours by the development of painful fluid-filled blisters. The blisters often burst, dry out and scab over within about 7 to 10 days.

Cold sores usually heal by themselves within about 10 days. Some things you can do at home to help treat your cold sore include: 

• take over the counter painkillers such as paracetamol and ibuprofen
• drink plenty of fluids like water or fruit juice
• eat food that is easy to eat such as soft foods and food that is not too hot
• avoid acidic or salty foods 
• use a high-factor sunblock if you go out in the sun

Over-the-counter treatments are available to help reduce symptoms and promote healing. 

• Cold sore creams like Zovirax (aciclovir) can help to relieve symptoms like pain, itching, and burning and may help your cold sore heal faster. 
• Cold sore patches contain a gel to help your cold sore heal and create a moist environment that reduces scabbing. They also provide a barrier that reduces the risk of bacteria infecting the cold sore and may lower the risk of passing the infection to others. You should still avoid direct contact with others while using a cold sore patch. 

If your cold sore lasts longer than 10 days, is severe, or if you keep getting cold sores, your GP may prescribe tablets called antivirals. 

Antivirals don’t cure cold sores but prevent the virus from reproducing in the body which may relieve symptoms and help your cold sore heal faster. They may also be used as a long-term treatment to prevent cold sores in people with weakened immune systems, or who get cold sores frequently. 

People with a weakened immune system, newborn babies, and pregnant women may need to be treated in hospital for cold sores. This may include giving antiviral medications intravenously (into a vein). 

How to prevent spreading cold sores to others

Cold sores are highly contagious from when you first develop symptoms until the cold sore has completely healed. To avoid spreading cold sores to other people:

• avoid close contact like kissing
• don’t share cups or eating utensils
• avoid touching your cold sore
• wash your hands before and after applying cold sore cream
• do not have oral sex until your cold sore has completely healed

An online doctor can help with cold sores by examining your cold sore, providing a diagnosis, and recommending further tests or treatments. Your online doctor can also advise you on things you can do to ease your symptoms and prevent future outbreaks. 

It’s easy to book an appointment with an NHS-trained GP at Medicspot. Simply click the link and select an appointment at a time and day that suits you. Appointments are often available the same day.

A pharmacist can help with cold sores by recommending over-the-counter treatments such as cold sore creams, patches, or painkillers. Electronic devices like lights or lasers are also available from pharmacies. There is currently limited evidence that these devices work, but some people find them effective. 

A cold sore is a common, but unpleasant viral infection that usually clears up without treatment. Over-the-counter treatments can help with symptoms and speed recovery, but if your cold sore is large, causing severe pain, or if you keep getting cold sores, make an appointment with a doctor. If you have a cold sore and would like to speak to a doctor, make an appointment today. 

NHS: Cold sores July 20th, 2020 (Accessed November 4th 2022) 

NIH: Cold sores overview July 12th 2018 (Accessed November 4th 2022)

NHS Inform: Cold sores April 2nd 2021  (Accessed November 4th 2022)

American Academy of Dermatology Association: COLD SORES: DIAGNOSIS AND TREATMENT (Accessed November 4th 2022)

PubMed: Human herpes simplex virus infections: epidemiology, pathogenesis, symptomatology, diagnosis, and management  November 2007 (Accessed November 4th 2022)

PubMed: Randomized clinical study comparing Compeed cold sore patch to acyclovir cream 5% in the treatment of herpes simplex labialis May 2008 (Accessed November 4th 2022)