Cold Sore Outbreak Overview

Prevalence, Symptoms, Stages, Safety, and Treatment

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Cold sores are caused by the herpes simplex virus type 1 (HSV-1). There is no cure for HSV-1. Once you contract the virus, it stays in your system for life.

The virus causes tiny blisters to form around the mouth and nostrils. The blisters pop and merge into a cold sore.

Anyone can get a cold sore. Most people contract herpes through physical contact with an infected person. You can infect others with your saliva even if you don't have a visible cold sore.

This article discusses the causes, symptoms, and stages of a cold sore outbreak. It also explores how to treat a cold sore and prevent future outbreaks.

Causes of Cold Sores

Herpes simplex virus 1 is very contagious. You can be exposed to the virus through physical contact with an infected person. This includes:

  • Intimate contact
  • Kissing
  • Sharing food or drinks
  • Sharing items like lip balm, razors, or towels

Research suggests genetics may make some people more susceptible to cold sores. The exact mechanism, however, is still unknown.

Once infected with herpes simplex, you will have the virus for the rest of your life. The virus usually stays dormant in the body. This means you won’t show any symptoms unless it is activated.

A number of factors can cause the virus to be activated. These include:

  • Stress
  • Fatigue
  • Hormonal changes, including menstruation
  • Illness
  • Dental work
  • Exposure to extreme weather
  • Sunlight


Research suggests that, worldwide, 67% of people ages 0 to 49 carry HSV-1.

cold sore stages
Verywell / Brianna Gilmartin 

Cold Sore Symptoms and Stages

Some people experience a cold sore outbreak within a few days of exposure. Other people carry the virus but never have symptoms.

A cold sore can last two to four weeks from early symptoms to completely healed. During that time, it goes through three distinct stages. These stages can vary between first outbreaks and recurrences.

Stage 1

The first stage of an outbreak lasts one to two days. During this time, tingling, itching, or even soreness around the mouth is common.

If this is a recurrence, you’ll likely feel this in the same locations as previous outbreaks.

Some people only experience this first stage and do not develop cold sores.

Stage 2

After a few days, small, hard, fluid-filled blisters begin to form on the lips, nose, cheeks, or other parts of the face.

At this stage, the blisters and fluid are very contagious. Avoid close physical contact with others.

Blisters can be spread to other parts of the body. If you touch a cold sore, wash your hands immediately. This will help you avoid spreading the virus to other areas.

Be especially careful to not touch your eyes after touching a cold sore.

See a doctor if you have:

  • Blisters near the eyes
  • Sensitivity to light
  • Pain or grittiness in the eyes

Children can develop cold sores inside the mouth. These are commonly mistaken for canker sores, which are small lesions in the mouth. If your child develops sores in the mouth, see a pediatrician for a diagnosis.

Stage 3

In the final stage, the blisters may merge and burst. This causes small, open sores that ooze fluid. These sores are very painful and highly contagious.

After a few days, the open sores begin to dry out and scab. Cold sore scabs can be very itchy and may crack. Avoid biting or picking at them. This can make the discomfort worse.

The scabs will begin to fall off and heal between five and 15 days after the sores first appear.

When To See a Healthcare Provider

The initial HSV-1 infection is usually the worst. This is because the body hasn't yet built up defenses to the virus. If you or a loved one experience the following, see a doctor:

  • High and persistent fever
  • Problems swallowing
  • Red, irritated eyes
  • Sores near the eyes
  • Trouble breathing

Also see a doctor if the sores last more than 15 days or reoccur frequently.

If you have a cold sore and a weakened immune system, call your doctor.

After the first infection, the virus remains inside the nerve cells of the face. Unless the virus is triggered to reactivate, you may not have symptoms again.

If you do have another outbreak, you can expect to develop a cold sore in the same place. The virus typically reactivates in the same spot each time. Symptoms, however, should be less severe in following outbreaks.


Cold sores often progress through three stages. In the first stage, you may have tingling and itching. In the second, blisters develop. In the third, the blisters burst and then scab over. 

Other Symptoms

During a first outbreak, you may also have flu-like symptoms in addition to a cold sore. These include:

Safety During a Cold Sore Outbreak

Cold sores are infectious until they scab over. If you have a cold sore, avoid:

  • Touching them
  • Kissing
  • Intimate contact such as oral sex
  • Sharing food, drinks, or personal items
  • Physical contact with anyone who has a weakened immune system
  • Physical contact with children

Cold sores can cause serious health issues in newborns, children, and people with weakened immune systems. It is important to take steps to avoid infecting others with HSV-1.

Treatment of Cold Sores

Cold sores cause pain, irritation, and even embarrassment. Fortunately, you can treat the pain and symptoms to feel better faster.


Certain prescription oral antiviral medications can shorten the duration of a cold sore. To work, these medicines need to be taken within 72 hours of an outbreak. These include:

  • Famvir (famciclovir)
  • Valtrex (valacyclovir)

Your doctor may recommend antiviral creams. These are applied directly to the cold sore. They include:

  • Abreva (docosanol 10% cream), available without a prescription
  • Denavir (penciclovir 1% cream)
  • Zovirax (acyclovir 5% cream)

Always wash your hands after applying topical medicines.

Over-the-counter pain relievers such as Advil (ibuprofen) or Tylenol (acetaminophen) can help relieve the pain, swelling, and irritation caused by blisters or open sores.

Home Remedies and Lifestyle

A cold compress can reduce pain and irritation. Use a cool, damp towel instead of an ice pack. Apply compresses a few times each day for five to 10 minutes at a time.

Otherwise, keep the affected area clean and dry. Don't put makeup over cold sores.

Stay away from foods that worsen symptoms. Acidic foods like citrus, tomatoes, or coffee can irritate cold sores and make symptoms last longer.

Your doctor can help you get your cold sores under control and avoid potential complications. These may include ocular herpes, which happens when HSV-1 transfers to the eyes. Other complications can include various skin infections.


Oral or topical antivirals may shorten an outbreak. Keep the area clean and avoid foods that might irritate the sore. A cold compress can also help.

Preventing Cold Sores

If you have frequent outbreaks, your doctor may prescribe daily Zovirax or Valtrex to help prevent outbreaks.

Depending on your triggers, you may also be able to prevent outbreaks without medication. For example, using sunscreen can help prevent outbreaks triggered by sun exposure.


Cold sores are caused by the HSV-1 virus. Once you contract this virus you will always carry it.

Symptoms include blisters around the lips, nose, and cheeks, which eventually break and form an open sore. During your first outbreak, you may also have flu-like symptoms. Subsequent outbreaks tend to be milder. See a doctor if you have sores near the eyes, frequent cold sores, or if symptoms last more than 15 days.

HSV-1 is very contagious. Avoid close contact with others and sharing personal items while you are having an outbreak.

Some treatments can shorten the duration of cold sores. These include prescription oral antivirals and topical antiviral creams. Cold compresses and over-the-counter pain killers may also help. Keep the area clean and don't eat foods that may irritate your cold sore.

You may be able to prevent frequent outbreaks with daily prescription medication. It also helps to avoid known triggers.

A Word From Verywell

Fortunately, cold sores tend to be harmless. They usually clear up within a few weeks.

If you develop symptoms of a cold sore outbreak or if you have recurrent outbreaks, talk to your doctor. They can help you find the best treatment plan for your age, medical history, and lifestyle.  

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7 Sources
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