When Is A Cold Sore No Longer Contagious?

Table of Contents

1. What Causes Cold Sores?
2. Why Are Cold Sores Contagious?
3. When Is a Cold Sore No Longer Contagious?
4. How to Avoid Spreading the Cold Sore Virus
5. How to Heal a Cold Sore

Key Takeaways

• Cold sores are caused by the highly infectious herpes simplex virus type 1 (HSV-1), which remains in the body permanently after the first infection.
• A cold sore is contagious from the initial tingling stage until it has completely healed, but it is most infectious when the blisters burst.
• Once a scab forms over the sore (typically around day 5-8), the chance of passing the virus on decreases significantly.
• The virus can be spread through skin-to-skin contact, such as kissing, or by sharing personal items like utensils, towels, or lip balm.
• To prevent spreading the virus, it is important to wash your hands frequently, avoid touching the sore, and refrain from intimate contact until the sore has scabbed over.
• While there is no cure, antiviral medications can help reduce the frequency of outbreaks and speed up the healing process.  

A very common virus called herpes simplex virus type 1 (HSV-1) causes cold sores. After the first infection, the virus remains in the nerve cells forever. Triggers like exposure to sunlight, fatigue, stress or hormonal changes activate the virus, making a cold sore appear.

Sores usually break out on or near the lips. There's no cure for cold sores, but antiviral medications may reduce the frequency of outbreaks.

The virus that causes cold sores spreads through skin-to-skin contact, which makes it highly contagious. According to the National Health Service (NHS), cold sores are most contagious when the blisters burst, but they are contagious from the tingling stage until healed.

The virus can spread to other people through kissing or sharing utensils. Touching cold sores and then touching the eyes can cause serious infections and vision problems.

A cold sore becomes much less contagious after it has formed a scab, says the American Academy of Dermatology. The fluid-filled blisters burst around four days after the first symptoms appear, and by five or eight days into the process, a yellowish or brown scab forms that reduces the chances of infection.

The scab begins to flake and fall off between days nine and 12, and finally the sore heals two to four weeks after the onset of symptoms. However, the Mayo Clinic states that people can pass on the virus even when they don't have any blisters. What's more, many people who have the virus never show any symptoms.

Good hygiene and avoiding close contact with others helps prevent spreading the cold sore virus while it's at its most infectious stage. Wash your hands often, and try not to kiss anyone or have intimate contact before the scab forms over a cold sore.

Don't share food or drinks or personal items like towels, razors or lip balm, and don't touch a cold sore unless you're applying medication. Wash your hands immediately afterwards. Additionally, people with active cold sores should avoid close contact with newborns and people who have weakened immune systems.

Cold sores resolve naturally, but you can try to help speed up the process with antiviral medications. Creams or pills containing certain ingredients may heal cold sores more quickly than no treatment.

Pain relievers like paracetamol, ibuprofen or benzocaine can help reduce the swelling and pain of cold sores and lessen the temptation to touch them. Popping the blisters and picking away the scabs won't heal cold sores any faster, and it may introduce bacteria that infect the sore and cause long-term scarring.

For most people, cold sores are annoying but rarely interfere with their everyday lives. That doesn't mean you want to share your cold sores with anyone else! Take sensible precautions if you feel a cold sore is on its way or the blisters haven't scabbed over, and the chances are good that you'll keep the infection to yourself.