Cold Sores

Cold Sores

What is a Cold Sore?

Sometimes called fever blisters, cold sores are small, red blisters that form around the mouth, often in patches or groups.

The skin around cold sores are often raised, swollen, and sore. These blisters may break open and leak a clear fluid, then scab over, before disappearing in around 2 weeks (or more).


Cold sores tend to happen in stages:

  1. A tingling, burning, or itchy feeling will begin in the area where a cold sore is beginning.
  2. In about 12-24 hours, blisters will form. This is when the area will become red, swollen, and painful.
  3. The blisters break open, and fluid leaks out; usually for 2-3 days.
  4. A scab will form on the cold sore, and may crack or bleed.
  5. The scab falls off, and the cold sore is healed.

Some people may experience a fever, muscle aches, or swollen lymph nodes.

In rare cases, eye symptoms may occur during a cold sore outbreak. In this case, speak to a doctor immediately, as untreated eye symptoms due to cold sores can lead to permanent vision loss.


Cold sores are caused by the herpes simplex virus (HSV).

There are two types of the herpes simplex virus: HSV-1, which usually causes cold sores, and HSV-2, which usually causes genital herpes. Though it is possible for either type of the virus to cause sores near the mouth and sores on the genitals.

Once infected, there is no cure, but it can be managed.

Risk factors

HSV-1 is one of the most common viruses in the world, with 90 percent of adults testing positive for it.

Once infected, it’s possible for the virus to reactivate. Some people may only get cold sores once, while others may experience them multiple times.

Certain risk factors can increase the chance of getting cold sores again, such as:

  • A weakened immune system
  • A flu, cold, or other illness
  • Sun exposure
  • Cold wind
  • Hormonal changes
  • Menstruation
  • Stress
  • Chemotherapy
  • Eczema

Are cold sores contagious?

Cold sores are contagious, and spread from person to person through close contact. Cold sores are even contagious when they’re not visible.

Usually, cold sores are spread through touching the cold sore, or the infected fluid. This can happen through kissing, sharing eating utensils, razors, or touching the infected person’s saliva.


To prevent spreading cold sores to others during an outbreak, an infected person should wash their hands frequently, and avoid sharing things that make contact with the mouth, such as utensils, lip balms, etc.

To prevent cold sores from returning, identify and avoid what triggers them.

For example:

  • If sun exposure is the trigger, use a sunblock lip balm with SPF-protection.
  • If stress is the trigger, practice techniques to manage and relieve stress.


Once infected, there is no cure for the HSV that causes cold sores, but treatment options are available to manage outbreaks.

Treatments can range from ointments and creams, to antiviral medications. Speaking to a doctor can help determine the best treatment option.

When to See a Medical Doctor

Everyone experiences cold sores differently. Some may only get one in their life, while others may get them regularly.

Though they will eventually go away on their own, they can be uncomfortable, embarrassing, and painful. Someone who gets cold sores regularly, or even for the first time, should speak to a doctor to figure out the best course of action.

There isn’t a cure, but there are plenty of treatment options available to manage and reduce the severity of cold sores, and their potential outbreaks.