Cold Sores vs. Herpes: What’s the Difference?

Cold sores and genital herpes are two distinct conditions caused by the herpes simplex virus (HSV). Both cause the outbreak of painful blisters and sores and both are highly contagious and incurable.

Cold sores are typically caused by herpes simplex virus type 1 (HSV-1), while genital herpes is most commonly caused by a closely related type called herpes simplex virus type 2 (HSV-2). But increasingly, more and more genital herpes cases are being caused by HSV-1 as the virus is passed from the mouth to the genitals through oral sex.

This article explains the similarities and differences between cold sores vs. herpes, including how you get them, what symptoms they cause, and how they are treated.

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Are Cold Sores Herpes?

Technically, both cold sores and genital herpes are herpes. Although many people will regard genital herpes as "herpes," the terms "cold sore" and "genital herpes" are largely logistical. Cold sores occur on the mouth and lips; genital herpes occurs on the genitals or rectum.

But the cause of the infection can sometimes vary.

Genital herpes (also known as herpes genitalis) can be caused by both HSV-1 and HSV-2. To a lesser extent, the same applies to cold sores (also known as herpes labialis or oral herpes). If you engage in oral sex, HSV-1 can be passed from the mouth to the genitals and HSV-2 can be passed from the genitals to the mouth.

But that doesn't mean that the viruses are indistinguishable or act exactly the same. While the two viruses share many of the same genetic and molecular characteristics, their differences influence how they cause symptoms, the transmission method, and the treatment.

Symptoms of Cold Sores vs. Herpes

HSV-1 and HSV-2 are incurable infections characterized by periods when the virus is dormant (latent) and periods when the virus is active. They are also characterized by recurrence during which the virus may spontaneously reactivate before being brought under control by the immune system.

During periods of reactivation, the virus will start to multiply rapidly and migrate from spinal root nerves where it is embedded to the surface of the skin. Once there, the virus can cause a localized outbreak of a painful blistering rash.

Or it may not. In fact, the vast majority of people with HSV-1 and HSV-2 are asymptomatic (meaning without symptoms) and may never have symptoms.

When symptoms do appear, they can vary based not only on the location of the outbreak but also on whether HSV-1 or HSV-2 is involved.

Symptoms of Cold Sores

Cold sores are mainly confined to mucous membranes of the mouth and lips but can also sometimes affect the skin of the face as well.

During reactivation, the virus will migrate up the trigeminal nerve that services the face and cause symptoms in three characteristic stages:

1. Tingling, itching, or burning may occur around the lips or mouth a day or so before the actual outbreak.
2. Small fluid-filled blisters will start to appear along the border of the lips (and sometimes around the nose or cheeks or inside the mouth).
3. Oozing and crusting will occur as the blisters merge, burst, and leave shallow, open sores.

Symptoms vary depending on whether this is your first or recurrent outbreak. If it is your first, the sores can take two to three weeks to fully heal. Subsequent outbreaks tend to be shorter.

Symptoms of Genital Herpes

Genital herpes is also mainly confined to mucous membranes of the genitals and rectum but can also affect the surrounding skin.

During reactivation, the virus will migrate up the lumbosacral dorsal root ganglia of the lower spine and cause symptoms in a similar pattern as with cold sores:

1. Tingling, itching, or burning may start around the genitals or rectum a day or so before the outbreak.
2. Small fluid-filled blisters will start to appear in moist tissues of the genitals or rectum (as well as the skin around the genital and sometimes the buttocks, groin, or thighs).
3. Oozing and crusting will occur as the blisters merge, burst, and leave shallow, open sores.

Symptoms again will vary based on whether this is your first or recurrent outbreak. If this is your first outbreak, the sores can take four to five weeks to heal. Subsequent outbreaks tend to be shorter and less severe.

How They Differ

By looks alone, it is hard—if not impossible—to tell if a herpes outbreak is caused by HSV-1 or HSV-2. With that said, there are differences.

The immune system generally has a harder time controlling HSV-2 than HSV-1. This is evidenced by vast differences in the rates of recurrence.

Studies have shown that 80% of people with HSV-2 genital herpes experience recurrence, whereas less than 20% of those with HSV-1 genital herpes experience recurrence.

This is an important distinction given that people with frequent recurrence may be given daily antiviral drugs to keep the virus under control. If it is found that the outbreak is caused by HSV-1, it can influence whether daily treatment is necessary.

Transmission of Cold Sores vs. Herpes

Both cold sores and genital herpes are highly contagious. Herpes is transmitted when the virus passes through broken skin or through mucous membranes that are far more porous.

During periods of reactivation, the virus can be passed not only through contact with sores but also through skin-to-skin contact with people who is otherwise asymptomatic.

This latter phenomenon, called asymptomatic shedding, occurs when a virus passes through the intact skin of someone who may not even be aware they have been infected.

There are specific routes of infection for cold sores and genital herpes as well as common ones, like oral sex.

What Causes Cold Sores?

Oral herpes is most commonly caused by HSV-1 and can occur at any stage of life, including childhood. According to the National Office of Health Statistics, around 60% of people in the United States will have HSV-1 by age 50.

In addition to open sores, HSV-1 is found in high concentrations in saliva. Because of this, oral herpes can be passed through:

• Kissing
• The shared use of lip balm, cutlery, or other objects that has touched another person's mouth

HSV-2 can also be passed from the genitals to the mouth during oral sex, although this is less common.

What Causes Genital Herpes?

Genital herpes is spread almost exclusively through sex. In the United States, infections are mainly seen after age 19. According to the Centers for Disease Control and Prevention (CDC) around 21% of people in the United States will get HSV-2 by the time they turn 50.

HSV-2 is passed through vaginal sex, anal sex, or oral sex. While uncommon, the virus may also be passed through shared sex toys.

While HSV-2 is considered the primary cause of genital herpes, an increasing number of infections are attributed to HSV-1 due to oral sex.

How They Differ

HSV-1 is readily passed from the mouth to the genitals. This is due in large part to the fact that rates of HSV-1 have been falling in recent years. As a result, fewer people have immunity to the virus by the time they are sexually active and are vulnerable to infection.

Some studies suggest that one in six new genital herpes infections are due to HSV-1. Others have concluded that more than half of all new genital herpes infections are caused by HSV-1 rather than HSV-2.

The same is not seen with HSV-2 and cold sores. Statistics suggest that HSV-2 is less likely to cause oral herpes. This may be due to the fact that many people will have gotten HSV-2 through sex and will already be immune to the virus.

Moreover, unless the skin of the lips is broken, HSV-2 may have a harder time establishing an infection compared to the porous tissues of the genitals.

Even with an HSV-2 genital herpes infection, the odds of an isolated non-genital outbreak (such as on the buttocks or thighs only) are pretty low.

Treatment of Cold Sores vs. Genital Herpes

There is no cure for HSV-1 or HSV-2 or any vaccines to protect against them. However, there are topical or oral antivirals that can reduce the severity and duration of an outbreak.

The antivirals most commonly prescribed are:

• Famvir (famciclovir)
• Valtrex (valacyclovir)
• Zovirax (acyclovir)

For people with frequent outbreaks, the drugs may be prescribed daily at a low dose to reduce the risk of recurrence as well as the risk of infecting others. This is called herpes prophylaxis.

The way in which the drugs are used can vary based on the location of the outbreak, the frequency of the outbreak, and whether you have HSV-1 or HSV-2.

How Do You Treat Cold Sores?

Valtrex is most commonly used to treat cold sores but Famvir can also be used. The drugs are generally prescribed as follows;

• Famvir: 1,500 milligrams (mg) in a single dose
• Valtrex: 2,000 mg every 12 hours for one day
  

Topical acyclovir and another topical antiviral called Denavir (penciclovir) can also be used, although they are generally less effective than oral drugs. Both are available by prescription.

An over-the-counter option is a topical cream called Abreva (docosanol) which can help shorten the length of an infection.

How Do You Treat Genital Herpes?

Zovirax, Valtrex, and Famvir appear equally effective for the treatment of genital herpes. The drugs are generally prescribed as follows:

• Famciclovir: 500 mg two times daily for five to 10 days
• Valacyclovir: 1,000 mg two times daily for five to 10 days
• Zovirax: 400 mg three times daily for five to 10 days

While genital herpes is not treated with topical antivirals, a topical anesthetic called lidocaine 5% ointment can be used to help ease the pain.

How They Differ

Beyond the obvious difference in dosages, the treatment of HSV-1 and HSV-2 can also vary if you are at risk of infecting a sexual partner. In such cases, you may be prescribed herpes prophylaxis if you are at risk of frequent recurrence.

In people with genital herpes, HSV-1 is far less likely to recur and will often be a once-off event. This is not the case with HSV-2 which recurs in most people.

Determining which type of HSV you have—using an antibody blood test—can influence the decision as to whether herpes prophylaxis is needed at not. If treatment is indicated, Valtrex is commonly prescribed as a 500-mg daily dose.

Summary

Cold sores (oral herpes) and genital herpes are both caused by the herpes simplex virus (HSV). Cold sores are mainly associated with herpes simplex virus type 1 (HSV-1), while genital herpes is mainly caused by herpes simplex virus type 2 (HSV-2).

Even so, HSV-1 is known to cause genital herpes in people who have oral sex. Less commonly, HSV-2 can be passed through oral sex and cause a cold sore. Without testing, it may be impossible to tell which type you have.

HSV-2 is far more likely to cause recurrence than HSV-1. It also is treated more aggressively and may require daily antiviral drugs to reduce the frequency and severity of outbreaks as well as the risk of infecting others.