Cold sores, also known as fever blisters, are painful and unsightly. They are caused by the herpes simplex virus type 1 (HSV-1) and can show up anywhere on the body. In most cases, they appear on the outside of the lips but can also show up on other areas. 

In this post, we’ll discuss when cold sores are the most contagious and how to prevent their spread. So read on to learn more about when are cold sores the most contagious.


Cold sores typically start off as a tingling or burning sensation in the affected area. This is followed by redness and some swelling. A cluster of small blisters may then form, which eventually break open and ooze a clear liquid. 

They can be very painful, and the area may also become itchy or sensitive. The blisters usually scab over after a few days and then gradually heal.

How Common Are They?

Cold sores are relatively common; about 90% of Americans have been infected with the herpes simplex virus that causes cold sores. However, not everyone who is infected will experience symptoms. Of those who do experience symptoms, some will get cold sores frequently, while others will only experience them rarely or even just once. 

If you have frequent cold sore outbreaks, it may be because you are under stress or have a weakened immune system. Illness, sunburns, and hormonal changes can also trigger an outbreak.

How Long Do Cold Sores Last?

The duration of a cold sore varies, but most will last 7 to 10 days. The blister will usually crust over within 3 to 5 days and then heal completely within a week or two. However, the virus that causes cold sores remains in your body for life and can reactivate at any time. The frequency of reoccurrence varies from person to person. Some people may experience several outbreaks a year, while others may only have one or two. 

Are Cold Sores Contagious?

Yes, cold sores are highly contagious and can be spread through direct contact with the affected area. 

When Are Cold Sores The Most Contagious?

Cold sores are most contagious when they’re in the blister stage. This is because the virus is actively replicating and shedding at this time. That said, you can still spread the virus even if you don’t have an active blister. 

In fact, you’re probably most contagious when you first start to feel a tingling sensation or see redness around your mouth—this is called the prodrome stage. Once the blister pops and begins to crust over, you’re less likely to spread the virus. 

How Are Cold Sores Spread?

Cold sores are spread through close contact with someone who has the virus. This can happen when you kiss someone or share eating utensils, razors, or towels with someone who has a cold sore. The virus can also be spread through contact with saliva, such as when someone with a cold sore performs oral sex on someone who doesn’t have the virus.

How Can You Stop Cold Sores From Spreading?

The best way to stop cold sores from spreading is to avoid close contact with people who have them. If you have a cold sore, avoid kissing people and sharing eating utensils, razors, and towels. You should also avoid oral sex until the sore has healed completely. 

If you must kiss someone or perform oral sex while you have a cold sore, it’s important to use a barrier method of contraception such as a condom or dental dam. This will help reduce the risk of spreading the virus to your partner. 

When Is A Cold Sore No Longer Contagious?

A cold sore is no longer contagious once the scab falls off. At this point, the virus has stopped shedding, and you can’t spread it to others. 

That said, you should still be careful about touching the area and washing your hands frequently. This will help prevent any bacteria from entering the sore, which could cause an infection.

How Are They Treated?

Cold sores usually heal on their own without treatment. However, if you find the blisters uncomfortable, there are a few treatments available. 

We will discuss some home remedies and medical treatments for cold sores below. 

Home Remedies For Cold Sores

There are a few things you can do at home to help relieve the discomfort of cold sores:

1. Apply a lip balm or cream. This will help to soothe and moisturize your lips, which can help to speed up the healing process. Be sure to choose a lip balm or cream that contains an SPF of at least 15 to protect your lips from the sun. 

2. Apply a cold, damp cloth to the sore. This will help to relieve pain and itching. Do this for five minutes at a time, several times a day.

3. Some essential oils, such as tea tree oil and peppermint oil, have antiviral properties that may reduce the duration of cold sores. 

5. Eat foods rich in lysine, such as fish, chicken, beef, tofu, eggs, milk, cheese, beans, lentils, and soybeans. Lysine helps to reduce the frequency and severity of outbreaks by limiting the amount of arginine that is available for HSV replication. 

Medical Treatments Cold Sores

If home remedies don’t provide enough relief, the following may be prescribed by your doctor:

1. Prescription antiviral medications such as acyclovir (Zovirax), famciclovir (Famvir), and valacyclovir (Valtrex) can help reduce the duration and severity of a cold sore. These medications should be taken as soon as you feel the tingling sensation that precedes an outbreak.

2. A topical cream called penciclovir (Denavir) can also be used to treat existing cold sores.

3. If you experience frequent or severe outbreaks, your doctor may prescribe oral antiviral medication taken daily as a preventative measure.

4. Corticosteroid injections may be used in rare cases when other treatments have not been effective.            

5. Photodynamic therapy uses light therapy combined with an applied cream called aminolevulinic acid (ALA). Photodynamic therapy has been shown to speed up healing time and reduce symptom severity. 

Can Cold Sores Be Serious?

Most of the time, cold sores are a minor annoyance. However, in some cases, they can cause serious complications. 

If left untreated, a cold sore can lead to an infection of the eye or other parts of the body. In rare cases, it can cause blindness if it spreads to the eye. 

It is also possible for cold sores to spread to other parts of the body, leading to more serious infections. If you experience any of these symptoms, it is important to seek medical attention right away. 

Additionally, people with weakened immune systems—such as those with HIV or undergoing chemotherapy—may be more prone to serious complications from cold sores. If you are immunocompromised, it is important to take extra precautions and speak to your doctor about the best way to manage cold sores. 

When To See A Doctor ?

If you experience any of the following symptoms, it is important to see your doctor right away:

• Your cold sores are not responding to home remedies or medications

• You have frequent outbreaks of cold sores

• Your cold sore is spreading to other parts of your body

• You are experiencing pain, swelling, or redness around the sores

• You have difficulty breathing, swallowing, or speaking due to a cold sore

• You develop a fever, headache, or body aches

Seeing your doctor can help you determine the best treatment for your cold sore and ensure that it does not spread to other parts of your body. It is also important to tell your doctor if you are immunocompromised. They can help you determine the best way to manage your cold sores and prevent any serious complications. 

Conclusion H2 

No one likes getting cold sores. But unfortunately, once you get HSV-1 (the virus that causes cold sores), it’s with you for life. However, there are a number of things you can do to manage your symptoms and speed up the healing process if you do happen to get one.

So if you find yourself with a painful blister on your lip, don’t despair—just follow the tips in this article, and it’ll be gone before you know it. And if your symptoms don’t improve, make sure to see a doctor right away to prevent any further complications. 

If you take the necessary precautions and live a healthier lifestyle, then you can avoid cold sores altogether and go back to living without worrying about an embarrassing blister on your face. You can also check our article on Everything You Need To Know About Cold Sores In Kids.

We hope that this article on “when are cold sores the most contagious” was helpful in understanding what cold sores are and how to manage them. Stay healthy and stay safe!