Cold sores can be annoying. At times it may feel unfair and like you’re the only person suffering from this natural smooch deterrent, but rest assured, the white blisters surrounding your lips are incredibly common.
Also known as ‘herpes labialis’, they are caused by the herpes simplex virus (HSV). There are two types of HSV – HSV-1 and HSV-2. Both can cause cold sores, but HSV-2 is spread via contact with the genitals so you’d have to kiss someone during oral sex to be infected.
A cold sore (or fever blister) outbreak will usually result in small white sores forming on or surrounding your lips. These typically heal within 2 weeks.
Cold sores are highly contagious, and you should not kiss another person until blisters have healed completely. That includes abstaining from oral sex.
How do cold sores spread?
Approximately half the people in the world are carriers of HSV-1. Some of them may never notice any signs or blisters on the lips, whilst others may be more prone to cold sore outbreaks and get them multiple times a year.
Herpes simplex is spread via touching of the skin and contact with bodily fluids such as saliva (but also genital fluids in the case of HSV-2). That means you could contract HSV-1 by:
- Kissing someone
- Sharing a toothbrush
- Sharing cutlery
- Using the same towel
- Oral sex
You should always avoid kissing someone with a cold sore because it could trigger a herpes flare-up in your partner.
When are cold sores contagious?
Cold sores are contagious during all stages of their development and healing process. That means you could easily spread HSV-1 or be responsible for another person breaking out during times when you have active sores.
Importantly, HSV-1 is infectious at all times, whether you have a cold sore or not. But you will be most contagious when the kiss blisters are opening up.
You should wait 3 to 4 days after your sores have disappeared before kissing someone.
I kissed someone with a cold sore. What should I do?
Don’t panic. Given that half the world population has HSV-1, there’s a good chance you do too.
The most important thing you can do is to monitor any breakouts. There is no way of knowing whether you will definitely get a cold sore if you kissed someone who has one. Your immune system may be strong enough to fight a flare-up.
If you notice redness developing around your lips, take an antiviral oral medication such as acyclovir, famciclovir or valacyclovir immediately. When treated early (within 48 hours of development), cold sores will heal much quicker.
You can also support your body’s natural defense mechanism by eating plenty of healthy foods, avoiding stress and exercising.
If you do not develop any symptoms, consider yourself lucky, but make sure you take measures not to pass on HSV-1 to others.
The time it takes for an outbreak to develop after kissing a person with a cold sore varies widely. It could take up to 20 days before you notice any signs that you contracted herpes.
I accidentally kissed my baby with cold sore. What should I do?
Neonatal herpes can be very dangerous because babies don’t have a well-developed immune system. The risk of passing on HSV-1 to a baby is highest during the first month after birth.
Go and see a doctor if you kissed your baby during your active breakout.
If you notice any of the following signs, seek an immediate appointment with your healthcare provider:
- Baby is not feeding
- Has a fever
- Has a skin rash or blisters on the eyes, mouth or skin
- Is irritable
You should seek urgent medical attention if your baby:
- Is difficult to wake up or becomes unresponsive
- Starts gasping for air, has trouble breathing or breathes rapidly
- Lacks energy
- Develops blue skin or a blue tongue
Your doctor will usually treat your baby with an injection of an antiviral drug. Often the parent will also be prescribed medication for faster treatment.
In most cases, babies make a good recovery. But make sure you seek treatment for your child immediately because if left too long, the virus can spread to the organs. A third of infants with neonatal herpes die this way.
When is it safe to kiss someone after a cold sore? In short, it’s never safe to kiss someone with a cold sore and it’s best to wait a few days after blisters have completely healed before kissing another person.
Remember, it can take 10 to 14 days for cold sores to heal. You can speed up the healing process by taking or applying an antiviral medication.
- WHO. (2017, January 31). Herpes simplex virus. Retrieved from Who.int website: https://www.who.int/news-room/fact-sheets/detail/herpes-simplex-virus
- Harvard Health Publishing. (2015, April 28). Cold sores - Harvard Health. Retrieved November 6, 2019, from Harvard Health website: https://www.health.harvard.edu/oral-health/cold-sores
- Opstelten, W., Neven, A. K., & Eekhof, J. (2008). Treatment and prevention of herpes labialis. Canadian family physician Medecin de famille canadien, 54(12), 1683–1687.
- James, S. H., Sheffield, J. S., & Kimberlin, D. W. (2014). Mother-to-Child Transmission of Herpes Simplex Virus. Journal of the Pediatric Infectious Diseases Society, 3 Suppl 1(Suppl 1), S19–S23. https://doi.org/10.1093/jpids/piu050
- Allen, U. D., Robinson, J. L., & Canadian Paediatric Society, Infectious Diseases and Immunization Committee (2014). Prevention and management of neonatal herpes simplex virus infections. Paediatrics & child health, 19(4), 201–212. https://doi.org/10.1093/pch/19.4.201