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Cold Sores

Is this your symptom?

  • Painful blisters on outer lip from cold sores

Some Basics...

  • Fever blister means the same thing as cold sore.
  • About 80% of adults have had a cold sore at some point in their lives.
  • The first time it happens is usually the worst. A person may get a fever or feel sick.
  • Some people can get cold sores more than one time.
  • Colds sores are caused by the Herpes simplex virus. This virus can be spread to other people by close contact like kissing.
  • There are medicines that can help sores heal faster.


  • First, a group of painful tiny (1-3 mm) small bumps or blisters appear on the outer lip. There can be 3-5 tiny blisters in a ½ inch (12 mm) area. The blisters are only on one side of the lip.
  • The blisters break and form 1 big sore (cold sore).


There are 2 types of cold sores: primary (first time) and recurrent.

Primary Herpes Simplex

  • This is the medical term for the first time a person gets a cold sore.
  • A person may feel sick and may have a fever.
  • There can also be sores inside the mouth.

Recurrent Herpes Simplex Labialis

  • This is the medical term for cold sores that happen more than once. About 1 in 5 adults will get cold sores more than one time.
  • After the first infection, the Herpes virus stays hidden in a facial nerve. The cold sore can come back after sun exposure, colds or fever, or with menstrual periods. A cold sore can also show up again because of stress or from being over-tired.
  • There is no fever.
  • The cold sore will get better without any treatment in 7-10 days.

Treatment - Over-the-Counter (OTC)

  • Docosanol cream (Abreva): this cream seems to help decrease the pain and duration of cold sores. It is FDA approved in the United States.

Treatment - Prescription Medicines

  • Topical (cream) with Pencylcovir 1%: use of this cream 4 times a day can help cold sores. It helps decrease the pain and duration of cold sores in adults. This cream costs more than docosanol.
  • Oral (pills): anti-viral drugs include acyclovir (Zovirax), famcyclovir (Famvir), and valacyclovir (Valtrex). These three drugs do not cure cold sores. However, they do seem to make the cold sores get better a little quicker. On average 1 day faster. Doctors do not treat every case of cold sores with one of these drugs.

When to Call for Cold Sores

Call Doctor or Seek Care Now

  • Sores on the eye, eyelids, or tip of nose
  • Red streak or red area spreading from the cold sore
  • You feel weak or very sick

Call Doctor Within 24 Hours

  • Have a weak immune system (HIV, cancer chemo, splenectomy, long-term steroid use)
  • New sores in other places
  • You think you need to be seen

Call Doctor During Office Hours

  • You are worried you might have an STI
  • You have frequent cold sores and want a prescription drug
  • Cold sore lasts more than 10 days
  • You have other questions or concerns

Self Care at Home

  • Cold sore and no other problems

Care Advice for Cold Sores

  1. What You Should Know:
    • Fever blisters or cold sores are found on one side of the outer lip.
    • They often last 7-10 days. Using a cold sore cream can help the sore heal faster.
    • You can treat cold sores at home.
    • Here is some care advice that should help.
  2. Abreva Cream (Docosonal 10%):
    • This cream seems to help decrease the pain and duration of cold sores.
    • Use this cream as soon as you feel the start of a cold sore. Rub this cream on the sore 5 times a day until it heals.
    • This cream is not sold in Canada.
    • Ask your doctor about the cream.
    • Read all package instructions.
  3. How It Is Spread:
    • Herpes from cold sores can be spread to other people. Try not to pick or rub the sore. Do not open the blisters. Wash your hands often. The cold sores can be spread for about 5 days until they are dry.
    • Before a sore appears, you may feel a tingling in your lip. During this time, you can spread your cold sore to others even if you cannot see a sore.
    • Eyes: Avoid spreading the virus to someone's eye by kissing or touching. An eye infection can be serious.
    • Mouth: Since the blisters can be spread, avoid kissing other people during this time. Avoid sharing cups, eating utensils, or razors.
    • Sex: Avoid oral sex during this time. Herpes from sores on your mouth can spread to your partner's genital area.
    • Avoid contact with people who have eczema or a weakened immune system.
  4. What to Expect: The pain should go away within 4-5 days. The sores often heal within 7-10 days. People often get cold sores 2 to 3 times per year.
  5. Prevention: Cold sores are often triggered by being in the sun. You should use a lip balm with sunscreen that is SPF 30 or higher.
  6. Sores Can Return: Tingling or burning where you had a cold sore in the past is a sign of a new sore.
  7. National Herpes Hotline: Phone number - (919) 361-8488. Here you will find information and advice for cold sores. The hotline is open Monday through Friday from 9 AM to 7 PM (Eastern Time).
  8. Call Your Doctor If:
    • Sores have spreading redness
    • Sores are near or in the eye
    • Sores last more than 10 days
    • You think you need to be seen
    • You get worse

And remember, contact your doctor if you develop any of the 'Call Your Doctor' symptoms.

Disclaimer: this health information is for educational purposes only. You, the reader, assume full responsibility for how you choose to use it.

Last Reviewed: 8/19/2019 1:00:25 AM
Last Updated: 3/14/2019 1:00:23 AM

Copyright 2000-2019 Health Navigator, LLC. All rights reserved.

Cold Sore of Lower Lip

Herpes simplex lesion of lower lip, second day after onset.

This is also called a "Cold Sore."

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