CNN

Cold sore symptoms include:

• Small, painful, fluid-filled blisters on a raised, red area of your skin, typically around the mouth
• Pain or tingling, called the prodrome, which often precedes the blisters by one to two days
• Usual duration of 10 to 14 days

Cold sores most commonly appear on your lips. Occasionally, they occur on your nostrils, chin or fingers. And, although it's unusual, they may occur inside your mouth — more often on your gums or the roof of your mouth. Sores appearing on other soft tissues inside your mouth, such as the inside of the cheek or the undersurface of the tongue, may be canker sores but aren't usually cold sores.

Signs and symptoms may not start for as long as 20 days after exposure to the herpes simplex virus, although it's more typical for sores to appear within about one week of exposure. Sores usually clear up within about two weeks. The blisters form, break and ooze. Then a yellow crust forms and finally sloughs off to uncover pinkish skin that heals without a scar.

When to see a doctor
Cold sores generally clear up on their own without treatment. However, see your doctor if:

• You have a pre-existing health condition that has compromised your immune system
• The cold sores don't heal within one to two weeks on their own
• Symptoms are severe
• You have frequent recurrences of cold sores
• You experience irritation in your eyes

©1998-2012 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.
Read this article on Mayoclinic.com.

Certain strains of the herpes virus cause cold sores. Herpes simplex virus type 1 usually causes cold sores. Herpes simplex virus type 2 is usually responsible for genital herpes. However, either type of the virus can cause sores in the facial area or on the genitals.

You get the first episode of herpes infection from another person who has an active lesion. Shared eating utensils, razors and towels, as well as kissing, may spread herpes simplex virus type 1. In addition, oral-genital contact may cause a genital form of herpes simplex virus type 1 infection.

Once you've had an episode of herpes infection, the virus lies dormant in the nerve cells in your skin and may emerge again as an active infection at or near the original site. You may experience an itch or heightened sensitivity at the site preceding each attack. Fever, menstruation, stress, fatigue and exposure to the sun may trigger a recurrence.

Cold sores and canker sores
Cold sores are quite different from canker sores, which people sometimes associate with cold sores. Cold sores are caused by reactivation of the herpes simplex virus, and they're contagious. Canker sores, which aren't contagious, are ulcers that occur in the soft tissues inside your mouth, places where cold sores don't typically occur.

©1998-2012 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.
Read this article on Mayoclinic.com.

Cold sores are contagious. They can pass from one person to another through skin-to-skin contact. The greatest risk of infection is from the time the blisters appear until they have completely dried and crusted over. There is a possibility of spreading the virus for some time even after the skin has healed.

If you have a cold sore, avoid close contact with infants, anyone who has eczema (atopic dermatitis) or people with a suppressed immune system, such as people with cancer, AIDS or an organ transplant. These people are at higher risk of more severe infection.

Herpes simplex infection of the eye causes scarring of the cornea and is a leading cause of blindness in the United States.

©1998-2012 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.
Read this article on Mayoclinic.com.

Cold sores generally clear up on their own without treatment. However, if you have lasting or severe sores, have frequent recurrences, or develop eye discomfort along with a cold sore, make an appointment with your family doctor or general practitioner.

Here's some information to help you get ready for your appointment, and what to expect from your doctor.

Information to gather in advance

• Write down your symptoms, including when they first began and how often you've had similar symptoms in the past.
• Make a list of all your medications, including any vitamins or supplements.
• Write down your key medical history, including other conditions with which you've been diagnosed. It will especially benefit your doctor to know if you have any conditions that weaken your immune system or if you're pregnant.
• Write down key personal information, including any recent changes or emotional stressors in your life.
• Write down questions to ask your doctor. Creating your list of questions in advance can help you make the most of your time with your doctor.

Below are some basic questions to ask your doctor about cold sores. If any additional questions occur to you during your visit, don't hesitate to ask.

• Do I have a cold sore?
• What treatment approach do you recommend, if any?
• What self-care steps can I follow to ease my symptoms?
• Am I contagious? For how long?
• How do I reduce the risk of spreading this condition to others?
• How soon do you expect my symptoms will improve?
• Am I at risk of complications from this condition?
• Is there anything I can do to help prevent a recurrence?

What to expect from your doctor
Your doctor is likely to ask you a number of questions. Being ready to answer them may reserve time to go over any points you want to talk about in-depth. Your doctor may ask:

• What are your symptoms, and when did they begin?
• Could you sense a cold sore coming before the sore became visible?
• How severe is your pain?
• Do your symptoms include eye irritation?
• Have you had similar sores in the past? How often?
• Have you noticed if anything in particular seems to trigger your symptoms?
• Have you been treated for cold sores in the past? If so, what treatment was most effective?
• Have you recently experienced significant stress or major life changes?
• Are you pregnant?
• Have you been diagnosed with any other medical conditions?
• What medications are you taking, including prescription and over-the-counter medications, vitamins, herbs, and supplements?
• Does your work or home life bring you into contact with infants or with people who have major illness?

©1998-2012 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.
Read this article on Mayoclinic.com.

Cold sores generally clear up without treatment within about two weeks.

Topical treatments that may help relieve your symptoms include:

• Lidocaine may provide short-term pain relief.
• Benzocaine (Zilactin) may protect cold sores from trauma and irritation. Benzocaine has been linked to a rare but serious, sometimes deadly, condition that decreases the amount of oxygen that the blood can carry. Don't use benzocaine in children younger than age 2 without supervision from a health care professional, as this age group has been the most affected. If you're an adult, never use more than the recommended dose of benzocaine and consider talking with your doctor.

Oral antiviral medications are available that may modestly shorten the duration of cold sores and decrease your pain, if started very early. These include:

• Acyclovir (Zovirax)
• Famciclovir (Famvir)
• Valacyclovir (Valtrex)

Your doctor also may prescribe an antiviral medication to prevent a recurrence of cold sores, particularly if you:

• Have very frequent bouts of cold sores
• Experience significant, related illness during a cold sore outbreak
• Have an identifiable trigger of cold sore recurrences — such as intense sunlight — and you anticipate exposure to that trigger

©1998-2012 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.
Read this article on Mayoclinic.com.

Cold sores generally clear up without treatment. In the meantime, the following steps may provide relief:

• Use ointments. Over-the-counter (OTC) ointments, such as topical lidocaine or benzocaine (Zilactin), can help ease discomfort. Benzocaine has been linked to a rare but serious, sometimes deadly, condition that decreases the amount of oxygen that the blood can carry. Don't use benzocaine in children younger than age 2 without supervision from a health care professional, as this age group has been the most affected. If you're an adult, never use more than the recommended dose of benzocaine and consider talking with your doctor.

• Take an OTC pain reliever. These include aspirin, acetaminophen (Tylenol, others) and ibuprofen (Advil, Motrin, others).

  Aspirin has been linked with Reye's syndrome, so use caution when giving aspirin to children or teenagers. Though aspirin is approved for use in children older than age 2, children and teenagers recovering from chickenpox or flu-like symptoms should never take aspirin. Talk to your doctor if you have concerns.

• Use cold or heat. Try applying ice or warm compresses to the blisters to ease the pain.
• Let it heal. Avoid squeezing, pinching or picking at any blister.

©1998-2012 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.
Read this article on Mayoclinic.com.

You can take steps to guard against cold sores, to prevent spreading them to other parts of your body or to avoid passing them along to another person. Cold sore prevention involves the following:

• Avoid kissing and skin contact with people while blisters are present. The virus can spread easily as long as there are moist secretions from your blisters.
• Avoid sharing items. Utensils, towels, lip balm and other items can spread the virus when blisters are present.
• Keep your hands clean. Wash your hands carefully before touching another person when you have a cold sore.
• Be careful about touching other parts of your body. Your eyes and genital area may be particularly susceptible to spread of the virus.
• Avoid triggers. If possible try to avoid or prevent conditions that stress your body, such as getting a cold or the flu, not getting enough sleep, or staying in the sun for long periods of time without applying sunblock.
• Use sunblock. Apply sunblock to your lips and face before prolonged exposure to the sun — during both the winter and the summer — to help prevent cold sores.

©1998-2012 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.
Read this article on Mayoclinic.com.