A cold sore is a blister on or around the lips caused by the herpes simplex virus (HSV). They start off small, grow larger over a period of a couple of days, and usually burst and scab over before healing. They’re not strictly a health risk, but they can be painful and unsightly. It’s easy to give them to someone else when you have them by kissing or sharing unwashed glasses or utensils (like cutlery). It can also be passed on from mothers to children.
Cold sores are caused by a virus that stays with you for life once you have it. Treatment doesn’t eradicate them completely, but if you use it early enough, it can stop them from developing and shorten the time it takes them to heal.
Outbreaks tend to happen when HSV, which can lie dormant for long periods, is reactivated. This can be brought on by various things like stress, being run down or an illness. It’s quite common for cold sores to spring up when your immune system isn’t at its strongest. So this might be if you’ve picked up another infection. It’s also possible to get them if you have the virus and get a lip injury (like a cut).
Herpes is often thought of as a sexually transmitted disease, but there are two types of herpes virus. Type 1 (HSV-1), which is the more common of the two, is more closely associated with cold sores. Type 2 (HSV-2) is more closely associated with genital herpes and tends to affect the groin and anal area. HSV-2 is more often passed on through sex. But either virus can be responsible for either symptom (cold sores or genital herpes).
Who gets cold sores?
Anyone can get a cold sore. There’s nothing that makes anyone more susceptible to infection than someone else with the virus. But if you have a weakened immune system, you’re more likely to get worse outbreaks more often.
Once you have the HSV virus, it stays with you for life and unfortunately, there isn’t a cure. But for most people, the outbreaks they get will become less severe and less frequent with age. Symptoms of cold sores will usually subside on their own after a couple of weeks, but treatment can help to speed this up.
Some people may get cold sore flare ups two or three times a year, while others could get one in their entire lives, and never have the issue again. So it’s quite dependent on the individual, and their health can be a factor in how many they get as well.
It’s common to get outbreaks if you’re stressed , or if your immune system is compromised after a bout of cold or flu. So keeping a healthy lifestyle is important to minimise flare ups.
How common are cold sores?
According to the WHO, an estimated two thirds of the world's population under 50 are infected with herpes simplex virus type 1 (HSV1) , that causes cold sores. But not everyone who has the herpes virus gets symptoms, meaning they would never know they had it.
A vast majority of HSV1 infections globally are oral herpes (infections in or around the mouth, sometimes called oral-labial or oral-facial herpes), but a proportion of HSV1 infections are genital herpes.
When we present you with stats, data, opinion or a consensus, we’ll tell you where this came from. And we’ll only present data as clinically reliable if it’s come from a reputable source, such as a state or government-funded health body, a peer-reviewed medical journal, or a recognised analytics or data body. Read more in our editorial policy.
What causes cold sores?
HSV is a lifelong virus you can get at any age. In the USA, over a third of children show evidence of HSV1 infections.
There are a few ways the herpes simplex virus can be transmitted. The most common one is through direct skin to skin contact such as kissing. Another common way it’s spread is through indirect contact with an infected person, like sharing eating or drinking utensils without washing them between uses or sharing items like lip balm. It can also be passed down from mother to baby.
You can also get cold sores through oral sex, or by sharing sex toys with someone who has genital herpes.
What are the symptoms of cold sores?
Cold sores usually start out as a localised tingling sensation before the blister shows up, but not everyone will get this early warning sign.
They normally pop up around the mouth and lips, but can also appear on the nose or chin. Once the infection has been ‘activated’, a small collection of fluid filled blisters will form. These can cause pain, tenderness and a burning sensation. The blisters eventually burst, and a crust forms over the affected area.
The virus is infectious just before, during and after cold sores are present. But even when the blister scabs over, you’re still infectious. HSV-1 is at its most infectious when your blisters have burst, but it stays infectious for a few days after your blisters have healed. So if you have a cold sore, it’s important to avoid kissing or sexual contact with others for a week after your symptoms have cleared up.
Can cold sores lead to other problems?
Cold sores by themselves don’t usually lead to any serious complications, but they can stick around for longer and be more severe in people with HIV or weakened immune systems.
Sometimes a HSV-1 infection can lead to problems like encephalitis or ocular disease, but this is mainly caused by spreading the infection from the lip to the eye (for example by touching the blister and then scratching your eye)
Because they appear on the face, it’s common for people with cold sores to feel self-conscious or anxious about them.
What medications are there for cold sores?
The main treatments for cold sores are antiviral topical creams and tablets. There are a few options, but most of these work in the same way, by stopping virus cells from replicating themselves.
Tablets tend to be used more when someone has severe outbreaks that don’t respond well to creams. But for most, creams tend to be enough.
Some treatments, like Aciclovir, come as a brand (Zovirax) and a generic (Aciclovir). There shouldn't be much difference in how well they work, but the company that makes them and the packaging they come in may be different.
Is there a ‘best’ treatment for cold sores?
Aciclovir (brand name Zovriax) is probably the most versatile treatment available for cold sores, because you can get it as a cream or as a tablet in a few different doses. Valaciclovir (brand name Valtrex) only comes in one dose as a tablet, but it might be helpful for you if you’re tried Aciclovir and it hasn’t worked.
If you aren’t sure which treatment is best for you, we can help. We’ll show you which treatments are right for you so you can choose the option you prefer.
Do cold sores always need treatment?
Cold sores are largely self-limiting. So they don’t always require treatment as the symptoms can clear up on their own within a couple of weeks. The main purpose of cold sore treatments is to speed up the healing process, and to stop a cold sore outbreak from fully developing..
While you have active cold sores, you’re more infectious. So using treatment can help to reduce the time that you have cold sores for, but also help to protect people you’re close to.
FAQ: Cold sores
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How are cold sores diagnosed?
Cold sores are really common, so a simple visual exam is usually enough to diagnose them. There are tests to check that what you have is HSV, but treatment can be recommended based purely on appearance. You’ll usually only need to have a follow-up with a doctor if the cold sore hasn’t started to heal within 10 days, if you’re particularly worried about a cold sore, or think it might be related to something else.
Are there any home remedies for cold sores?
Applying a clean cold compress directly to the cold sore may help soothe irritation and reduce inflammation and redness. But it probably won’t help your lesions to heal faster than treatment would.
It’s important not to aggravate cold sores by scratching or biting them, or trying to peel off the skin around the blisters, because this can make them worse (meaning they’ll take longer to heal).
Can you get side effects from cold sore treatment?
You can get side effects from cold sore treatment, but the risks of serious side effects are low as long as you use the treatment correctly. The risk of side effects for tablets is longer than it is for topical creams, because the drug in the tablets is taken up into your bloodstream (the cream works locally).
The most common side effects with creams are skin irritation and redness. Common side effects of the tablets are headaches or nausea. If you’ve used treatment before and had side effects, talk to us, and we’ll make sure you get the right advice on which option is best for you.
Do cold sore treatments always work?
There isn’t a cure for cold sores, so treatment focuses on easing symptoms. These are generally effective at shortening the duration and reducing the severity of symptoms. For example in clinical trials, people using Zovirax cream shortened the length of their outbreak by half a day. .
If your cold sores don’t respond to treatment or persist for longer than 10 days, let us know. It may be that you need to try a different type of treatment or a stronger dose.
Why should I buy cold sore treatment online with Treated?
We know that getting help for cold sores isn’t always easy, and how important it is to get treatment quickly so you can catch symptoms before they develop.
We can help you find the treatment you need. Talk to us about your health so we can get to know what you’re looking for, and we’ll recommend cream and tablet options for you. We’ll also check in with you after your treatment has started to make sure it’s working well for you.
Stress Hormones Epinephrine and Corticosterone Selectively Modulate Herpes Simplex Virus 1 (HSV-1) and HSV-2 Productive Infections in Adult Sympathetic, but Not Sensory, Neurons. Journal of Virology, 91(13). [Accessed 7 Aug. 2021].
Disclaimer: The information provided on this page is not a substitute for professional medical advice, diagnosis, or treatment. If you have any questions or concerns about your health, please talk to a doctor.
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