So, are cold sores contagious? Absolutely. And they can easily spread to others. In fact, you can spread a cold sore to someone else through person-to-person contact or by direct contact with body fluid on inanimate objects, such as towels, eating utensils, and razors.

According to the American Academy of Dermatology, approximately half of people aged 14-49 have herpes simplex virus (HSV), which can lead to fever blisters or cold sores. Furthermore, by age five, most people have their first cold sore outbreak.

What Causes Cold Sores?

Cold sores, sometimes called fever blisters, are fluid-filled bumps caused by the infectious virus, herpes simplex virus type 1 or type 2. Both types of the herpes simplex virus (HSV) can cause cold sores. Cold sores due to HSV-1, or oral herpes, are mainly present as small blisters around the mouth or on the lips. HSV-2, or genital herpes, can cause cold sores around the mouth and lip area. However, a person transmits HSV-2 through sexual contact.

Once you have HSV of any type, the virus remains in your body throughout your life. However, the virus, which remains dormant, can become active during events such as stress or illness. For example, the following events can trigger a cold sore breakout.

• Hormonal changes 
• Cold, flu, or fever 
• Stress
• Sun exposure
• Poor diet and dehydration 

Remember that not all people with HSV will experience a cold sore flare-up.

Can I Spread a Cold Sore to Someone Else Through Kissing?

Cold sores are contagious, so you can pass oral herpes to someone else through kissing. Because the virus lives in saliva, others should avoid contact with your cold sore and the surrounding area. Unfortunately, you can also transmit the virus through kissing, even if you do not have any fluid-filled blisters. Below are some common signs and symptoms that may occur before a cold sore outbreak:

• Fever
• Sore throat
• Painful swallowing
• Nausea
• Swollen glands
• Burning feeling in the mouth
• Headache

If you have eczema or your cold sore flare lasts longer than two weeks, you have cold sores in your eyes, or you get cold sores multiple times a year, make an appointment to see a dermatologist. Remember, the virus that causes cold sores remains dormant in the body between outbreaks; therefore, your symptoms may be milder with each subsequent episode.

Dangers to Newborns

According to a case study, HSV-1 infection can lead to severe complications in babies younger than six months. A child's first cold sore outbreak usually occurs between six months and five years old. Therefore, avoiding kissing or touching newborns is essential if you have any signs and symptoms of HSV-1 or blisters in or around your mouth. 

Is It Possible to Spread a Cold Sore to Someone Else Through Shared Items Such as a Towel or a Cup?

You can spread cold sores to others when you share personal items, cups, or even towels. Cold sores spread through skin-to-skin contact, but you can transmit infected saliva or body fluid to inanimate objects or hard surfaces. The following list is just some items that can cause cold sores from person-to-person.

• Towels
• Washcloths
• Razors
• Eating utensils
• Water bottles
• Drinkware
• Drinking straws
• Lip balm/lipstick
• Toothbrush

If you develop symptoms of HSV or a cold sore, be careful not to share your personal items with anyone else.

Are Cold Sores Contagious Through Contact with an Infected Person's Body Fluids?

Cold sores are contagious through contact with an infected person’s body fluids. Body fluids include saliva, semen, and fluid in the vaginal canal. An infected person remains contagious from the first sign of infection to the final healing stage. Although the timeline for each stage may vary for each person, the lifespan of a cold sore is typically about two weeks without treatment.

Stages of a Cold Sore

This first stage happens a few days before a cold sore is visible. You may feel a burning sensation and tingling on and around the mouth area. Young children and infants may have poor eating and drinking habits because of mouth soreness.

After two to four days, fluid-filled blisters appear in small clusters around the lips or mouth during the second stage.

Around day four, blisters leak fluid or weep, causing ulcers. Leaking fluid from blisters is the most contagious stage because an infectious person can expose someone to the fluid from the cold sores.

The open ulcer will eventually crust over with a scab. Unfortunately, cold sores are still contagious at this stage of healing. The scab formation may take five to eight days.

The final stage is the healing phase, which happens from ten days to two weeks after the first noticeable signs and symptoms. After that, the cold sore is completely healed, without scabbing and minimal scarring, if any.

During each stage of HSV infection and cold sore formation, remember that you are still contagious and should refrain from touching the infected area. In addition, get in the habit of frequently washing your hands so that you don't inadvertently pass the virus on to someone else or spread the virus to other parts of your body.

How Can I Reduce the Chances of Spreading a Cold Sore to Someone Else?

You can prevent the spread of cold sores to others by taking some practical steps. As stated, cold sores spread through skin-to-skin contact or exposure to an infected person's body fluids. Below are some precautions you can take to prevent the spreading of the virus.

• Frequent hand washing
• No kissing during an outbreak
• Do not share drinkware and eating utensils with others
• No sharing personal items such as towels or washcloths
• No sexual contact during an outbreak
• Prescription medication to speed recovery

Are Cold Sores More Contagious in the Early Stages of an Outbreak?

As previously mentioned, a cold sore is contagious throughout an outbreak. However, when the fluid-filled blister ruptures, you increase the likelihood of passing the cold sore to someone else through mucous membranes in the mouth or genital area.

When to See Your Healthcare Provider

While there is no cure for HSV, prescription antiviral medicines can shorten the recovery time of cold sores and prevent future outbreaks. If you have any pre-existing conditions, like a weak immune system, HIV/AIDS, eczema, or are receiving chemotherapy, you are at a higher risk for cold sores. See your healthcare provider to ensure you don't develop any complications.

Cold sores can be a nuisance, but if you ever have them, you can speak to your healthcare provider, who will let you know if a prescription for an antiviral medication can help speed up your recovery time. While you recover, you can protect your family by avoiding kissing and sharing personal items.

References

Aloyouny, A. Y., Albagieh, H. N., & Al-Serwi, R. H. (2021). Oral and perioral herpes simplex virus 

infection type I in a five-month-old infant: A case report. World journal of clinical cases, 9(3), 685–689. https://doi.org/10.12998/wjcc.v9.i3.685. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7829727/ 

American Academy of Dermatology Association. (n.d.). Cold sores: Overview. https://www.aad.org/public/diseases/a-z/cold-sores-overview

American Academy of Pediatrics. (2017, July 11). Cold sores in children: About the herpes simplex virus. Healthychildren.org. https://www.healthychildren.org/English/health-issues/conditions/skin/Pages/Herpes-Simplex-Virus-Cold-Sores.aspx

Mayo Clinic. (n.d.). Cold sore. 

https://www.mayoclinic.org/diseases-conditions/cold-sore/symptoms-causes/syc-20371017?p=1

Orenstein, B. W. (2013, July 8). How Contagious Are Cold Sores?. Everyday Health. https://www.everydayhealth.com/skin-and-beauty/how-contagious-are-cold-sores.aspx

Silver, N. (2023, March 27). Cold sore stages: What can I do? Healthline.

https://www.healthline.com/health/skin-disorders/cold-sore-stages 

World Health Organization. (2023, April 5). Herpes simplex virus. https://www.who.int/news-room/fact-sheets/detail/herpes-simplex-virus

Author Bio

Kimberly Madison, MS, RN, is a freelance health content writer with over 13 years of experience as a registered nurse. She creates high-quality blog content, health news articles, web copy, infographics, and patient education materials for hospitals and healthcare brands.