Oral Herpes Testing

Oral herpes, or herpes labialis, is a common skin infection that's transmitted through non-sexual oral contact with infected saliva, mucous membranes, or skin. It's caused primarily by herpes simplex virus type 1 (HSV-1). The second type of herpes, genital herpes, is a sexually transmitted disease usually caused by herpes simplex virus type 2 (HSV-2).

Key Points

  • 1 About 48% of Americans between the ages of 14 and 49 have HSV-1
  • 2 Prevalence increases with age and is 5.7% more common among females than males
  • 3 Sores typically heal on their own within 7-14 days, but there’s no cure for HSV.
  • 4 Infected persons can transmit HSV-1 to another person through their saliva or cold sores.

Published January 3, 2020
Written by Anita Wong

Oral herpes is asymptomatic, which means that some people with the infection may not show symptoms. Symptoms that do appear take the form of cold sores and fever blisters on or around the lips. Oral herpes does not pose a serious outcome to healthy adults and children but can be dangerous to newborns.

HSV-1 infection is common throughout the world, with the World Health Organization estimating that 67% of people under the age of 50, or 3.7 billion people, have the virus. According to the Centers for Disease Control and Prevention (CDC), about 48% of Americans between the ages of 14 and 49 had HSV-1 in 2015-2016. Its prevalence increased with age and was 5.7% more common among females than males.

This guide provides basic information on oral herpes. Find out what an infection looks like, how it spreads, and why some people may not know that they’re infected. We also discuss options for testing, what the results may mean, treatment, and recovery time.

General Information
Infectious Organism Herpes simplex virus type 1
Other Commonly Used Names Oral herpes, cold sores, fever blisters, herpes labialis, nongenital herpes simplex virus
Testing Collection Method Swabs, blood
Transmission Saliva, kissing, shared utensils, razors or toothbrushes
Prevention Wash hands frequently, avoid touching cold sores and avoid oral contact or sharing of personal items when sores are present.

Overview of Oral Herpes Testing

The purpose of herpes testing is to screen for a herpes simplex virus infection. However, the CDC doesn’t recommend routine screening for herpes if you don’t have symptoms.

Herpes testing is recommended if:

  • You’re experiencing symptoms in the genital area that could be related to herpes
  • Your current or previous sexual partner has genital herpes
  • You’re pregnant, and you or your partner have or had symptoms of genital herpes
  • You’d like a complete screening for sexually transmitted diseases and have had multiple sexual partners

Most health care providers diagnose oral herpes based on a physical examination of cold sores and a patient history to determine if you’ve been in contact with a person with HSV. Your physician may, at their discretion, request a swab or blood test to confirm that your cold sores are caused by HSV.

How an Oral Herpes Infection Works

An oral herpes infection is commonly acquired in childhood through non-sexual oral contact with an infected person. It appears in the form of cold sores or fever blisters on the lips, mouth, and tongue. HSV is asymptomatic, so while some people may have sores, others don’t even know they have the virus.

Sores typically heal on their own within 7-14 days, but there’s no cure for HSV — an infection remains with you for life. There may be recurring outbreaks of the cold sores, but frequency decreases over time.

Infected persons can transmit HSV-1 to another person through their saliva or cold sores. This could be through kissing or sharing a cup, fork, toothbrush, or razor. It’s most easily spread when sores are present but can be transmitted even if symptoms aren’t present. This is called asymptomatic reactivation or shedding, meaning the virus lays dormant and is occasionally reactivated.

Oral herpes is not a major health concern for most healthy children and non-pregnant adults. HSV can be life-threatening in newborns as their immune system is still developing. Babies may get HSV-1 from close contact with someone who’s shedding the virus in their saliva, such as a caregiver. They may also get HSV-2 from their mother during vaginal birth.

It’s possible for a person with HSV-1 to spread it to the genital area through oral sex. An increasing number of cases of genital herpes are caused by HSV-1, mostly in Europe, North and South America, and countries in the Western Pacific region. It’s rare, however, for HSV-2 to cause oral herpes as most adults already have HSV-1.

If you have an HSV-1 infection, your body has developed antibodies, and you’re unlikely to get HSV-1 in another part of your body. However, you can still get genital herpes from HSV-2.

Stages of Oral Herpes

Primary Stage

The first sign of oral herpes is a small, sometimes painful, skin blister that’s filled with a clear, cloudy, or yellowish fluid. It may appear as a single blister or cluster of blisters. The blister then becomes red and swollen, eventually breaking open and leaking fluid. The open sore then develops a crust or scab as it heals. It takes about 7-14 days for a cold sore to heal.

The severity of cold sores or fever blisters varies. Some people may experience very mild symptoms or mistake a small cold sore for a bug bite or pimple.

Latent Stage

HSV-1 then retreats into the sensory nerve ganglia or the point where nerve endings meet. During this stage, it remains dormant and conceals itself from the immune system. The virus has its own sleep-wake cycle and periodically reactivates to ensure its survival.

Asymptomatic Reactivation (Shedding)

When the virus is awakened, it begins multiplying. If the virus is in nerve endings that are close to body fluids — for example, HSV-1 is typically in the nerve ganglia behind the cheekbone — it enters and is transmitted through those fluids. Shedding occurs even when symptoms are not present.

Recurrence

About one-quarter of people with HSV-1 will experience a recurrence, sometimes triggered by sunlight, stress, or fatigue. Often, there’s a prodrome, or warning sign, that a recurrence is about to begin. You may feel pain, itching or tingling a day or two before the cold sore appears. It’s a good idea to assume the HSV-1 is active and take care to avoid spreading the virus.

Variations of Oral Herpes

  • Oral herpes or herpes labialis involves cold sores on or around the lips.
  • Oral-facial herpes affects the upper lip, nose, cheek, and chin.
  • Complications can occur in those with compromised immune systems. HSV-1 is one of the viruses that can cause encephalitis (inflammation of the brain) or keratitis (eye infection), but this is rare.

Symptoms of Oral Herpes

In addition to the presence of fever blisters and cold sores around the mouth, the following symptoms of oral herpes may appear:

  • Newborns may experience fever, become lethargic, or have seizures.
  • Young children may also experience fever or flu-like symptoms.
  • Adults may have a sore throat and lymph node swelling.

If you have symptoms, avoid kissing people on the mouth, performing oral sex, or sharing items such as cups and utensils.

While some people experience severe or mild symptoms, others may not have any symptoms.

Testing for Oral Herpes

If your physician examines your lesions and decides further testing is required, several tests may be performed to confirm that the sores are caused by HSV.

HSV DNA Test

Also known as a nucleic acid amplification test or polymerase chain reaction (PCR), this test looks for the genetic material or DNA of the herpes simplex virus from a sample collected from a lesion. It’s three times more likely to detect HSV than a viral culture and has less chance of a false negative.

The test typically involves collecting a specimen from a cold sore.

  • A specimen collection swab is inserted into the lesion.
  • The skin is swabbed to collect a specimen.
  • The sample is placed in a collection vial and transported to a lab for testing.

No preparation is required.

Herpes Viral Culture

A viral culture involves adding a sample collected from a cold sore to certain cells to check for the presence of HSV. If the herpes simplex virus infects the cells, the test is positive. If it doesn’t, the test is negative. Lesions that are tested within a few days of an outbreak, before they begin healing, are more likely to test positive than those tested later. False negatives are possible.

The test typically involves collecting a specimen from a cold sore.

  • A specimen collection swab is inserted into the lesion.
  • The skin is swabbed to collect a specimen.
  • The sample is placed in a collection vial and transported to a lab for testing.

No preparation is needed.

HSV Antibodies Blood Test

If sores aren’t present, a blood test can check for the presence of antibodies — the blood protein that your body produces to fight a virus or bacteria. If you’re infected with HSV, your body develops antibodies to HSV, even if you’re not exhibiting symptoms. A blood test may check for HSV in general, or specifically for HSV-1 or HSV-2.

The test involves collecting a blood sample from an arm vein.

  • The area of the arm where blood will be drawn, such as inside the elbow, is cleaned and disinfected.
  • A rubber band is tied around the upper arm to increase blood flow and make it easier to draw blood.
  • A small needle is inserted into the arm to collect a blood sample in a small tube.
  • The needle is removed and gentle pressure and/or a bandage is applied to the puncture site.
  • The tube with the sample is sent for testing.

No preparation is needed.

Treatment for Oral Herpes

While there’s no cure for oral herpes, this type of infection isn’t considered a major health concern for healthy adults and children. Cold sores and fever blisters generally clear up within 7-14 days without treatment. If you find them painful, ask your doctor about antiviral medicines in the form of creams or pills to relieve discomfort.

Newborns that are infected with HSV-1 may become sick quickly because their immune systems aren’t strong enough. They’re at risk of brain damage and death and require immediate hospitalization and intravenous medication.

Frequently Asked Questions


  • Should I be tested for oral herpes?

    The CDC recommends herpes testing only if you have genital symptoms.

    If you have symptoms of oral herpes, your physician may be able to diagnose based on appearance of the sores and where they’re located. If further confirmation is required, your physician may recommend testing.

    Herpes testing is available through your doctor, local health department, community health clinic, or a Planned Parenthood center.


  • Why doesn’t the CDC recommend testing for oral herpes?

    STD screening is only recommended for infections that have serious outcomes if left untreated. Cold sores may be painful and annoying, but for most healthy adults and children — except newborns — it’s harmless and clears up on its own.

    Although herpes is common, some people may feel there’s a stigma attached to the virus. A positive test result can cause unnecessary shame and an emotional burden. If you’re concerned about oral herpes, speak with your physician about testing.


  • Can an oral herpes test tell me when I became infected?

    No. A herpes test can determine if you’re infected, but it can’t tell you when or how long you’ve been infected.


  • What’s important to know about oral herpes?

    Oral herpes is asymptomatic, so you can have the virus and transmit it without ever demonstrating symptoms. There’s no cure for herpes, and recurrences are possible, but they decrease in frequency and severity over time. If you’re otherwise healthy, there’s little risk of a serious outcome.


  • What does a positive result for oral herpes mean?

    If your HSV viral culture, HSV DNA test, or HSV antibodies blood test comes back positive, you have a herpes simplex virus infection.

    Exercise caution if you have symptoms. Avoid touching the sores, wash your hands frequently, and avoid oral contact such as kissing or oral sex.


  • What does a positive test result for HSV-1 mean?

    If you were tested for the type of herpes simplex virus and your results come back positive for herpes simplex virus type 1, you have an HSV-1 infection.

    Unless you’ve experienced symptoms, it’s difficult to know whether this means it’s an oral or genital infection. While most cases of HSV-1 infection are oral, there are increasing cases of HSV-1 oral to genital transmission.


  • What does a positive test for HSV-2 mean?

    If you were tested for the type of herpes simplex virus and your results come back positive for herpes simplex virus type 2, then you have an HSV-2 infection.

    Unless you’ve experienced symptoms, it’s likely a genital infection. An oral herpes infection from HSV-2 is possible but rare.


  • What does a negative result for oral herpes mean?

    A negative test means it’s unlikely you have an HSV infection, but false negatives do occur.

    An HSV viral culture or DNA test is most accurate when samples are collected from a lesion before the sore has started to heal, as more of the virus is present. If the sample is collected later, it may result in a false negative.

    If you test negative for HSV antibodies through a blood test, it means you haven’t been infected by HSV, but this can be a false negative if antibodies haven’t yet formed at the time the test was taken. Antibodies may take up to 16 weeks to develop in your body.


  • How long does it take to get test results?

    Times vary, but it generally takes 1-3 days for the results of an HSV DNA test and 2-14 days for an HSV viral culture. A blood test for HSV antibodies takes about two days, although there’s a rapid test that may have results in 2 hours.

Additional Resources

  • John Hopkins Medicine provides an in-depth review of oral herpes, including symptoms and treatment options.
  • For parents, PKIDSs online, has information on helping to reduce the spread of oral herpes among family members and how to decrease irritation.

Find out how dermatologists diagnose and treat oral herpes at the American Academy of Dermatology Association’s website.