All about Cold Sores (Oral Herpes)

shutterstock_64505920A patient came in this morning with a cold sore on her lip and was asking about treatment options.  She was wondering if this might be a sexually transmitted infection.  He’s never had a cold sore before that she can remember, but her boyfriend has genital herpes.

Cold sores are blisters that can be extremely painful.  They are usually near the lips or inside the mouth.  Herpes simplex virus is the cause of these blisters.  There are several types of herpes virus.  Type 1 usually causes cold sores while type 2 usually causes genital herpes that affects the penis or vaginal area.  A patient may have type 1 that occurs in the genital area or type 2 that affects the mouth but this is rare.  To answer this patient’s question about whether she could have got herpes on her lip from her boyfriend with genital herpes – the answer is “yes, it is possible.”

What are cold sores and how do I know if I have them?  These are actually also called fever blisters and are painful sores that usually occur near the mouth or lips.  The first time a patient gets cold sores is usually when they are a young child.  They can occur on the lips, mouth, nose or throat and usually form a small blister that pops and then forms a scab.  They are usually very sore and can also be associated with body aches or fever.

Sometimes people think they have a cold sore when instead they might have a canker  sore which is not caused from a virus.  The first time a patient has cold sores, the symptoms are usually more severe than when they get them in the future.  The initial attack can last 10-14 days and there are usually more ulcers than just one.  Patients complain of pain, burning, tingling or itching around their mouth sometimes even before the blister forms.

A medical provider can usually diagnose a cold sore, but they are so common that once you’ve seen them or have had them in the past, you can usually recognize them yourself.  If you have questions about a sore around your mouth however it’s always a good idea to have it checked by a medical provider.

How are cold sores spread?  The herpes virus that causes cold sores spreads easily from one person to the next usually by kissing or sharing a beverage container or eating utensil such as a spoon.  It can also be spread by people who have oral sex with someone who has genital herpes.   Once you have been infected with cold sores once, even after the sores go away the virus stays in your body in the nerve fibers under the skin.  More sores can come out any time and can be spread to other people.  Cold sores often re-occur when you become sick or your immune system is under stress.

Do I need to see a medical provider if I get a cold sore?  If you have severe pain, increasing redness or swelling around the mouth, nose or lips or trouble swallowing you should probably be seen by a medical provider.  Sometimes cold sores can become secondarily infected with a bacteria and cause a cellulitis or abscess that needs to be treated with antibiotics.  If a sore around the mouth is not going away, it’s also important to have it checked out to make sure that it’s not a cancer or something unexpected.

How do I get rid of cold sores?  The first time someone has cold sores the infection is usually worse and treatment is often recommended.  The virus can be treated with medication however there is no treatment to totally cure someone who has had cold sores or the herpes infection because the virus continues to exist in the nerve fingers under the skin even after the blisters go away.  If the sores come back after the initial infection, the symptoms are usually not as severe and usually go away within 8 days or less and there is usually less pain.

People with mild symptoms of cold sores often do not require treatment.  Patients often ask for medications to help reduce the duration of the cold sores or to treat the pain that accompanies the blisters.  I usually recommend ibuprofen or naproxen for pain relief due to the blisters.  There are various over the counter treatments which are helpful to some patients with cold sores including various creams or gels such as Abreva.  Abreva works by stopping the virus from entering into your cells and blocking the virus’ ability to replicate.  Patients also often get relief by using Orajel which is a topical numbing medicine that relieves that pain but does not make the viral infection go away any faster.

Oral prescription medication are sometimes prescribed for cold sores if they are severe.  Acyclovir, valacyclovir, and famciclovir are common oral antiviral medications that can be used for severe oral herpes infections.  Acyclovir seems to work the best for most people.  These antiviral therapies are usually most effective if started within the first 2-3 days of symptoms.  Some patients take chronic antiviral medications to prevent recurrent outbreaks of cold sores if:  recurrences are frequent or bothersome to the patient (ie. associated with frequent disfiguring lesions and pain) or for patients who have frequent serious systemic complications such as erythema multiforme, eczema herpeticum, or recurrent asceptic meningitis.

How can I prevent getting cold sores?  As I mentioned above, if you get cold sores frequently or they are associated with serious other conditions your doctor may prescribe a medication to take every day or periodically to prevent infections.  If you already have cold sores, avoid excessive sunlight as this has been shown to trigger cold sores to return.  Decreasing stress, getting enough sleep and staying healthy are some common sense ways of hopefully reducing your chances of developing recurrence of cold sores.  When you have a cold sore, do not kiss anyone or share silverware, glasses or cups, lip balm or razors.  Avoid oral sex when cold sores are present.

This document is for informational purposes only, and should not be considered medical advice for any individual patient.  If you have questions please contact your medical provider.


I hope that you have found this information useful.  Wishing you the best of health,

Scott Rennie, DO



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