What is a cold sore?

A cold sore consists of a group of small, painful blisters that appear around the mouth and lips, and in some cases, the nose, cheeks and inside the mouth. Cold sores are caused by the herpes simplex virus (HSV). They’re also known as herpes simplex labialis or fever blisters. 

The symptoms of a cold sore are usually most severe the first time you get one. Once you experience the first outbreak, your body will create antibodies. Some people will never have another infection, but others do. 

Are cold sores herpes?

A cold sore is a form of herpes. The herpes simplex virus type 1 (HSV-1) causes cold sores, whereas the herpes simplex virus type 2 (HSV-2) causes genital herpes. Even though HSV-1 commonly causes cold sores around the mouth and lips and HSV-2 causes sores around the genitals, both viruses can cause sores in both areas. 

How common are cold sores?

Cold sores are extremely common. Up to 90% of the population have experienced HSV1. However, it’s important to note that cold sores aren’t usually a serious medical condition and there are many things you can do to treat your symptoms. 

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Cold sore symptoms

In most cases, cold sores will appear around the mouth and lips. Once you are infected with a cold sore, it can take up to 20 days for them to develop. The sore usually emerges close to where the virus entered your body. As well as the sore, some people may experience red or swollen gums, swollen neck glands, muscle aches or a fever. 

What does a cold sore look like?

When cold sore blisters first appear, they normally look like small, fluid-filled bumps that are surrounded by red and swollen skin. Once the blisters burst, the cold sore will heal and appear as a dry scab. 

Stages of a cold sore

Cold sores will normally appear in stages. This means you won’t suddenly develop an open sore on your face and can use preventative medication to reduce your symptoms before they start showing. The stages are as follows: 

1. A tingling, itching or burning feeling. 
2. Around 6-48 hours later the area will become red, swollen and painful as blisters form.
3. The blisters will break open and fluid may ooze out which will last 2-3 days. 
4. A scab will form over the sore and it may crack or bleed. 
5. The scab will fall off and the blister will heal fully within 10-14 days in most cases

How long does a cold sore last? 

Cold sores will usually take around 10 days to clear up on their own, but this varies between people. What triggers your cold sores and their severity can affect the time it takes to fully recover. Fortunately, there are things you can do to promote faster healing and ease the pain. 

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Cold sore causes

The herpes simplex virus is responsible for cold sores. HSV-1 is mainly responsible for cold sores on the face, whereas HSV-2 commonly causes sores around the genitals. However, both types of the herpes simplex virus can cause sores on the face or genitals. Most people are exposed to the virus from a young age through close skin to skin contact with an infected person. 

How do you get a cold sore?

Cold sores spread from person to person through close contact with an infected area. This can be through kissing or sharing food or drink with people who carry the virus. It can spread to the genitals through oral sex, which is why you should always wear protection when being intimate. 

You’re more likely to catch HSV from someone who carries the virus and has symptoms, but you can also catch it from people who don’t have any symptoms.

When is a cold sore contagious?

A cold sore is contagious from their first stage which consists of a tingly, itchy or burning feeling in the affected area and it will remain contagious until it has completely healed. You should avoid sharing food or drink with people, having oral sex, or kissing loved ones as soon as you notice the early signs of a cold sore. Being cautious will prevent the spread of cold sores. 

If you pass your cold sore onto a baby, it can cause neonatal herpes which can be a serious condition as their immune systems are not fully developed. Young babies with herpes infections always need to see a doctor urgently. 

I kissed someone with a cold sore. What should I do?

Cold sores are highly contagious. If you kiss someone who has a cold sore, even if it isn’t visible on their face, then you have a high chance of contracting HSV and developing cold sores at a later date. Unfortunately, there isn’t much you can do if you contract the virus as there is no cure, but treating the cold sore in its early stages can sometimes prevent it from fully developing. 

What triggers a cold sore?

Once you have contracted HSV, cold sore outbreaks can occur at any time. However, in most cases, something will trigger the occurrence of an open sore. Avoiding these triggers and making healthy changes to your lifestyle can reduce the risk of developing a cold sore. Some triggers can include but are not limited to: 

• Extreme temperatures – hot sun and cold wind. 
• The cold virus or another illness or infection. 
• A weak immune system. 
• Hormone changes. 
• Stress and fatigue. 

Some people will never learn what their triggers are, whereas others will feel like each cold sore is triggered by something different. Keeping track of your cold sores is advisable not only for pinpointing your triggers but for recording how long it lasts and whether you treated it effectively.

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Cold sore treatment

There is no cure for HSV, but there are things you can do to treat your cold sore when you experience an outbreak. Though treatment of an uncomplicated cold sore is not essential, acting fast with the right medication can reduce the length and severity of your symptoms.

Is there a cure for cold sores?

There is no cure for the virus that causes cold sores. In most cases, cold sores will heal by themselves and will clear up in around 7-10 days. However, if you use antiviral creams and cold sore tablets correctly, it could help speed up the healing process while reducing your symptoms. 

How to treat a cold sore

Cold sore tablets and creams can be used to treat a cold sore as soon as you start to feel a tingling, itching or burning sensation around your lips, mouth or face. Cold sore patches are a good option for cold sores that have already caused blistering on the skin as they offer protection to the infectious area and promote healing. 

Cold sore tablets

Cold sore tablets can be taken to treat illnesses that are caused by HSV, including cold sores and genital herpes. Your doctor may prescribe you cold sore tablets if you’ve suffered from infections before or if you have a weak immune system. 

Cold sore creams

Cold sore creams can not cure the infection or stop it from spreading to other people. They can stop an outbreak by being applied to the symptomatic area during the early stages, but they can’t be used on an open sore. We do not provide cold sore creams, but you may be able to purchase these from your local pharmacy.

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Cold sore triggers

Cold sores tend to come back when your immune system is weakened. Looking after your health will help you avoid recurrent bouts. Everyone is different and you will need to observe your symptoms to identify the herpes triggers which affect you. Common trigger for cold sores include:

• an infection (for example a cold or the flu)
• emotional and physical stress
• having a high fever
• being tired or exhausted
• injury to the lips or mouth
• hormonal changes (including menstruation in women)
• exposure to sunlight

Once you have figured out what your cold sore triggers are you will find it easier to avoid outbreaks.

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Where can I get Cold Sore tablets?

You can conveniently buy cold sore medication from most online UK registered pharmacies like Superdrug Online Doctor. Topical treatments for cold sores are available over the counter. Your GP may be able to prescribe cold sore tablets on the NHS but this will depend on your medical history and local prescribing guidelines.

Can I buy Cold Sore Tablets online?

You can buy cold sore tablets online from UK registered pharmacies, like Superdrug Online Doctor. To order this medication you will have to complete a short and simple medical form, so our doctors can review it and treat you safely. If they think it’s right for you, they’ll prescribe the medication for you to order with free home delivery. 

Can I get Cold Sore Tablets over the counter?

No. Cold sore tablets are only available on prescription. Topical treatments, such as cold sore creams, are available over the counter. 

Can I get Cold Sore Tablets on the NHS?

You may be able to get cold sore tablets on the NHS. Whether you are prescribed these depends on your medical history, the severity of your condition and local prescribing guidelines . The severity of your cold sore will determine the best treatment for you. It’s best to consult with a doctor if you’re suffering from your first cold sore and require treatment. 

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Cold Sores Tablets Side Effects

The side effects of taking a commonly used cold sore tablet (aciclovir) will vary between individuals. The following side effects are common and occur in more than 1 in 10 to 1 in 100 people who take aciclovir: 

• Headaches. 
• Dizziness. 
• Nausea or vomiting. 
• Abdominal pain. 
• Diarrhoea. 
• Itching or an itchy rash. 
• Skin is sensitive to sunlight. 
• Tiredness.
• Fever.

If you experience any of the above side effects and they’re bothering you or not going away, then you should talk to your doctor or pharmacist. You don’t need to stop taking the medicine unless any of the symptoms are severe or you start getting symptoms associated with an allergic reaction like trouble breathing or swelling of the face or lips. If this does happen, you should stop using the medication immediately and call 999. 

If you have a fever it’s always important to contact a doctor to check for any other underlying causes for this. It’s important to read the information leaflet to check a full list of potential side effects, interactions and contraindications before taking any medication. 

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Are Cold Sore Tablets right for me?

Cold sore tablets and other medications are usually effective but they may not work for everyone. If you’re unsure about whether this treatment is right for you, then you should contact your doctor or pharmacist to ensure you’re making the right decision for your health. If you’re taking other medication, then a medical professional can tell you if it’s safe to take both medicines together. 

List of contraindications

If you’re under 18, pregnant or breastfeeding, elderly, suffer with kidney problems or have a suppressed immune system it’s important to talk to your doctor before you start this treatment. You shouldn’t take cold sore tablets if you’re allergic to active ingredients in the medicine or similar medications. 

Medications that interact with cold sore tablets

You must tell your doctor if you’re taking any of the following medications before taking cold sore tablets like aciclovir: 

• Aminophylline or theophylline for asthma. 
• Cimetidine for stomach ulcers.
• Mycophenolate mofetil after an organ transplant. 
• Probenecid for gout. 
• Certain medications used in the treatment or prevention of HIV

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Sources

Aciclovir (including Zovirax) (2019) NHS [accessed 03 November 2021]

Cold Sore (2021) NHSinform [accessed 03 November 2021]

Cold Sores (2020) NHS [accessed 01 November 2021]

Scenario: Herpes labialis (cold sores) and gingivostomatitis (2021) NICE [accessed 26 November 2021]

Aciclovir Tablets BP 400mg (2020) EMC [accessed 29 November 2021]

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