Cold sores – little blisters that develop on the lips or around the mouth – are caused by the herpes simplex virus (HSV). They are also common, with one in five people in the UK thought to be affected by recurring cold sores (i).
The first symptom of a cold sore is usually an itchy, tingly or burning sensation. Within 48 hours one or more fluid-filled sores will form. These sores may weep before crusting over and eventually healing within seven to 10 days. When they rupture – and up until they have healed completely – they are at their most contagious (ii).
Most people are first infected with HSV during childhood, typically via contact with a family member who has a cold sore. But you can catch the virus at any age through direct contact with someone who already has it (by kissing them, for example) or from something a cold sore sufferer has used – such as a cup, toothbrush, towel, lipstick or lip balm.
The strain of the virus that most commonly causes cold sores is the HSV-1 virus, but in a few cases cold sores can also be caused by the HSV-2 virus if someone has oral sex with someone else who has genital herpes (iii).
If you’re an adult, the first infection of the virus doesn’t usually cause any symptoms. Children under the age of five, however, may develop a sore throat, irritated gums, mouth sores, high temperature, headache and nausea when first infected with HSV (iii).
Once you’ve contracted the virus, it takes up residence in a nerve sheath. For some people, the virus stays dormant and never causes any symptoms. But for others it becomes activated, multiplies and travels down the nerve sheath to cause an outbreak of cold sore blisters on or around the mouth. If you have the HSV virus that becomes activated, you may only have cold sores once in your life. On the other hand you may get them every now and then or much more frequently (iii).
Cold sore triggers
Experts still don’t really know what makes a dormant virus active, but there are certain things that are thought to trigger it, including stress, illnesses such as colds and flu (or other conditions that cause a raised temperature), tiredness, feeling run down, female hormones (some women find they get cold sores at certain times of the month) and strong sunlight or UV light (from a sun bed, for instance). There again, in many cases there may be no evident trigger.
Cold sore treatments
There is no cure for cold sores, so if you’ve been infected by the cold sore virus you will have it for life. The good news is that cold sores usually clear up without any treatment within seven to 10 days. There are, however, several things that may help prevent or treat outbreaks, including the following:
There is some evidence to suggest putting sunscreen on and around your lips and mouth may help prevent cold sores if you’re one of the people for whom strong sunlight or another form of UV light is a trigger (iv). As with any sunscreen application, the higher the SPF and UV star rating, the better the protection (use a minimum of SPF15). And as well as using a general sunscreen product, you could also try a lip balm that has built-in SPF.
These are available over the counter at pharmacies and include ingredients such as aciclovir and penciclovir. There isn’t any clear evidence about how well these creams work, but if you use them as soon as you feel the first signs of an outbreak they may make your cold sores less painful and help them to heal more quickly (v).
Research shows that antiviral tablets – the most widely used being aciclovir – can help treat cold sores. Studies suggest they reduce pain and speed up healing in children who have cold sores when they are first infected with the virus (vi), and that they may reduce the recurrence of cold sores and reduce the length of time symptoms last in adults (vii). However, antiviral tablets can cause side effects such as headache, nausea and diarrhoea. Doctors also only usually prescribe antiviral tablets for babies and children or adults who get a very bad attack of cold sores, or for adults with cold sores who also have an immune system deficiency problem.
Cold sore patches
Also available over the counter, cold sore patches contain a special gel and are placed on top of sores before they rupture, sealing them and helping them to heal. They can also help to camouflage an unsightly cold sore and are thought to stop the virus from spreading.
Cold sore creams
As well as antiviral creams, you can buy creams that don’t contain antiviral ingredients. These non-antiviral creams may not help heal cold sores faster, but they may be useful for easing pain and irritation.
Devices to treat cold sores that emit infra-red light are also available, and may be helpful in some cases. These devices are available at pharmacies.
Pain relief medicines
You can also relieve the pain of cold sores by taking over-the-counter painkillers, such as ibuprofen or paracetamol.
How to stop cold sores spreading
If you already have cold sores, it’s important to try to prevent the virus infecting other parts of your body as well as other people.
Here’s some advice that may help:
If you have a cold sore, don’t share anything that comes into contact with the affected area, including lipstick, lip balm, cups, glasses, toothbrushes, cutlery, flannels, razors or towels.
Avoid touching your cold sores (only touch them when you’re applying creams). Remember to be gentle when you’re applying cold sore creams – try not to rub them in, as this can cause further damage to your skin.
Try not to pick at the sores as this could infect them with bacteria or even transfer the virus to other parts of your body (it may also slow down healing).
Whenever you apply cold sore cream, wash your hands thoroughly with soap and water both beforehand and afterwards.
Never let someone else use your cold sore cream.
Avoid kissing or having any close physical contact with anyone – including oral sex – while you have a cold sore until it has healed completely.
Also be particularly careful to avoid contact with certain people whenever you have a cold sore, including pregnant women, newborn babies and those who have a low immune system (such as people who have HIV or who are having chemotherapy).
Cold sores: how to help yourself
As well as using cold sore treatments, there are a few things you can do to help yourself:
Many people find they get cold sores whenever their stress levels are high. While you may not be able to do anything to prevent stress, you can learn to stay more calm in stressful situations. One way to do this is to learn relaxation techniques, such as deep breathing or meditation. Also try to reduce your general stress levels by doing something you find generally relaxing. Do something every day that you enjoy and that makes you feel good, whether that’s having a long relaxing bath, watching your favourite TV programme or reading a good book.
If you have a cold sore, put some ice on it for a few minutes a couple or more times a day, as it can help ease pain and irritation. Never apply ice directly to your skin: wrap some ice in a clean cloth before applying, or use an ice pack designed for cold therapy that you can keep in the freezer. Keep your lips moist If you’re susceptible to cold sores, try to prevent your lips from drying out or cracking. Use a lip balm to keep them moisturised – ideally use a product with sun protection, especially when you go outdoors.
Eat more protein
Foods rich in an amino acid called L-lysine may help to keep cold sores at bay. Good sources of lysine are foods that are high in protein, including fish, meat, eggs and cheese. Lysine is also found in avocado, kidney beans, corn and beetroot.
Meanwhile, you may want to avoid foods that contain another amino acid called arginine, as some nutritional practitioners believe it may play a part in reactivating the HSV virus. Arginine-rich foods include poultry, seafood, peanuts, chocolate, whole-grain cereals and gelatine.
However, the problem with lysine and arginine is that many foods contain both amino acids, so it may not be easy to eat more or less of one without eating more or less of the other too.
Natural remedies for cold sores
There are a few natural supplements that may prove useful in treating and preventing the outbreak of cold sores.
As well as eating more foods rich in the amino acid – or protein – L-lysine, you could also try taking supplements to boost your intake. For instance, one study suggests taking lysine every day for six months could significantly reduce your risk of having a cold sore flare-up (viii).
Other studies have found taking lysine daily may improve the frequency of cold sore attacks (ix). Interestingly, a study into whether or not lysine may be effective when taken at the onset of a flare-up had negative results (x), which may suggest taking lysine daily is a more effective way of protecting against regular cold sores.
High-strength multivitamin and mineral
Some other nutrients – such as zinc (xi) and vitamin C (xii) – may also be effective in protecting against cold sores. The most convenient way to make sure your intake of these nutrients is at a decent level may be to take a good-quality multivitamin and mineral.
According to a review of studies into herbal remedies and their effect on viral infections including HSV, elderberry (Sambucus nigra) is one of a few plants that may have promising antiviral activities (xiii). Elderberry extract may also help when you have a cold sore by boosting your immune system, thanks to the way it’s thought to increase the body’s production of chemical messengers within the immune system called cytokines (xiv).
If you have recurring cold sores, it can have a disrupting effect on your day-to-day life. This guide may give you a few ideas to help you manage them more effectively. If you’d like to learn more about a range of other common health conditions, feel free to visit our health library.
Available online: https://www.nhs.uk/conditions/cold-sores/
Rooney. JF, Bryson. Y, Mannix. ML, et al. Prevention of ultraviolet-light-induced herpes labialis by sunscreen. Lancet. 1991; 338: 1419-1421. Available online: https://www.ncbi.nlm.nih.gov/pubmed/1683420
Duteil. L, Queille-Roussel. C, Loesche. C, et al. Assessment of the effect of a sunblock stick in the prevention of solar-simulating ultraviolet light-induced herpes labialis. Journal of Dermatological Treatment. 1998; 9: 11-14. Available online: https://www.tandfonline.com/doi/abs/10.3109/09546639809160682
Spruance. SL, Rea. TL, Thoming. C, et al. Penciclovir cream for the treatment of herpes simplex labialis. Journal of the American Medical Association. 1997; 277: 1374-1379. Available online: https://www.ncbi.nlm.nih.gov/pubmed/9134943
Ducoulombier. H, Cousin. J, DeWilde. A, et al. Herpetic stomatis-gingivitis in children: controlled trial of acyclovir versus placebo. Pediatric Annals. 1988; 35: 212-216. Available online: https://www.ncbi.nlm.nih.gov/pubmed/3288078
Amir. J, Harel. L, Smetana. Z, et al. Treatment of herpes simplex gingivostomatitis with aciclovir in children: a randomised double blind placebo controlled trial. BMJ. 1997;314: 1800-1803. Available online: https://www.bmj.com/content/314/7097/1800
Spruance. SL, Rowe. NH, Raborn. GW, et al. Peroral famciclovir in the treatment of experimental ultraviolet radiation-induced herpes simplex labialis: a double-blind, dose-ranging, placebo-controlled, multicenter trial. Journal of Infectious Disease. 1999;179: 303-310. Available online: https://academic.oup.com/jid/article/179/2/303/997771
Baker. D, Eisen. D. Valacyclovir for prevention of recurrent herpes labialis: 2 double-blind, placebo-controlled studies. Cutis. 2003;71: 239-242. Available online: https://www.ncbi.nlm.nih.gov/pubmed/12661753
Griffith. RS, Walsh. DE, Myrmel. KH, et al. Success of L-lysine therapy in frequently recurrent herpes simplex infection. Treatment and prophylaxis. Dermatologica. 1987;175:183-190. Available online: https://www.karger.com/Article/Abstract/248823?&utm_medium=112819
McCune. MA, Perry. HO, Muller. SA, et al. Treatment of recurrent herpes simplex infections with L-lysine monohydrochloride. Cutis. 1984;34:366-373. Available online: https://www.ncbi.nlm.nih.gov/pubmed/6435961
Milman. N, Scheibel. J, Jessen. O. Failure of lysine treatment in recurrent herpes simplex labialis [letter]. Lancet. 1978;2:942. Available online: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(78)91658-6/fulltext
Godfrey. HR, Godfrey. NJ, Godfrey. JC, et al. A randomized clinical trial on the treatment of oral herpes with topical zinc oxide/glycine. Altern Ther Health Med. 2001;7:49-54, 56. Available online: https://pubmed.ncbi.nlm.nih.gov/11347285/
Hovi. T, Hirvimies. A, Stenvik. M, et al. Topical treatment of recurrent mucocutaneous herpes with ascorbic acid-containing solution. Antiviral Res. 1995;27:263-270. Available online: https://pubmed.ncbi.nlm.nih.gov/8540748/
Akram M. et al., Antiviral Potential of Medicinal Plants Against HIV, HSV, Influenza, Hepatitis, and Coxsackievirus: A Systematic Review. Photother Res. 2018 May;32(5):811-822.Available online: https://pubmed.ncbi.nlm.nih.gov/29356205/
Barak. V, Halerpin. T, Kalickman. I. The effect of Sambucol, a black elderberry-based, natural product, on the production of human cytokines: I. Inflammatory cytokines. Eur Cytokine Netw. 2001 Apr-Jun;12(2):290-6. Available online: https://pubmed.ncbi.nlm.nih.gov/11399518/
Disclaimer: The information presented by Nature's Best is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications.
Christine Morgan has been a freelance health and wellbeing journalist for almost 20 years, having written for numerous publications including the Daily Mirror, S Magazine, Top Sante, Healthy, Woman & Home, Zest, Allergy, Healthy Times and Pregnancy & Birth; she has also edited several titles such as Women’ Health, Shine’s Real Health & Beauty and All About Health.