Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Skin Problems & Treatments Health Center

Cold Sores - Symptoms

Cold sores are blisters on the lips and the edge of the mouth that are caused by an infection with the herpes simplex virus (HSV).

Cold sore blisters usually break open, weep clear fluid, and then crust over and disappear after a few days.

Other symptoms may include:

You may not develop cold sores when you are first infected with HSV. If cold sores do develop when you are first infected, they may be more severe than in later outbreaks. During the first outbreak of cold sores, the blisters may spread to any part of the mouth.

After you become infected, HSV remains in your body and may cause cold sores to return throughout your lifetime (recurrent cold sores).

Recurrent cold sores usually develop where facial skin and the lip meet. About 6 to 48 hours before a cold sore is visible, you may feel tingling, burning, itching, numbness, tenderness, or pain in the affected area. This is called the prodromal stage.

Some common triggers that cause cold sores to return include:

People who have weakened immune systems are more likely than those with strong immune systems to have longer or more severe outbreaks of cold sores. HSV infection may be life-threatening in certain people who have weak immune systems.

Who is at greatest risk for developing cold sores?

Anyone who is exposed to the herpes simplex virus (HSV) is at risk for developing cold sores. But many people have the virus and may never develop cold sores.

People who have weakened immune systems are at an increased risk for having more severe and longer-lasting outbreaks of cold sores.

One form of HSV infection is seen most often in children 1 to 3 years old. This type of HSV infection (primary herpesstomatitis) can cause a high fever and blisters throughout the mouth, which can interfere with the ability to eat. It can be serious in children-they can get quite sick from this illness, although they usually recover without any long-term problems.


WebMD Medical Reference from Healthwise

Last Updated: June 04, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
Next Article:

Today on WebMD

Pictures and symptoms of the red, scaly rash.
woman with dyed dark hair
What it says about your health.
woman with cleaning products
Top causes of the itch that rashes.
atopic dermatitus
Identify and treat common skin problems.
itchy skin
shingles rash on skin
woman with skin tag
Woman washing face
woman washing her hair in sink
close up of womans bare neck
woman with face cream