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Oral Herpes: The Basics

Oral Herpes: The Basics
Valacyclovir 500mg tablets 

What is Oral Herpes?

Oral herpes (cold sores) are caused by the herpes simplex virus type 1 (HSV-1) or type 2 (HSV-2), however the majority of cases are caused by HSV-1.

How Common is Oral Herpes

Infection is common. Worldwide, an estimated 66% of the population has HSV-1.  In the United States, one study showed that approximately 36% of all 12-13 years had HSV-1.(1)

Risk of Infection

HSV-1 spreads when someone with no prior infection comes into contact with herpetic lesions, secretions or has skin contact that contains HSV-1.  The virus can be spread even when there are no signs of symptoms of infection.  Most HSV-1 infections occur during close but not necessarily sexual contact.  Family members often act as sources, and children can contact it day care centers where saliva sharing behavior - sharing cups, play objects - often occurs.

HSV-1 can also be transmitted though sexual activity, and studies have shown that athletes involved in contact sports like wrestling are also at risk.

Oral Herpes Symptoms

Many oral herpes infections do not cause of symptoms or cause only mild symptoms that can easily be mistaken for another condition.  If symptoms do appear, the first time they do (primary infection) typically occurs 2 to 12 days after exposure, and appear as small painful skin lesions in or around the mouth that may take one to two weeks to fully heal, without treatment.  This is referred to as having a first herpes “outbreak.”

There are differences between the first herpes outbreak and subsequent outbreaks.  The first outbreak is typically the most severe, the herpetic lesions tend to last longer and are often accompanied by systemic symptoms like fever, sore throat, headache, and body aches.  Recurrent oral herpes is thought to occur in a minority of individuals infected with HSV-1 and can be associate with “triggers” like stress, fever, or exposure to sunlight; dental procedures can also trigger an outbreak.  Most patient develop prodromal symptoms sometimes a day before the painful oral herpes lesions appear.  Prodromal symptoms can include tingling or burning, itching at the site or near the site of a previous outbreak. Recurrent lesions typically appear on the vermillion border of the lip but can occur inside the mouth and are characterized by painful blisters that evolved into shallow ulcers that crust in five to eight days, without therapy.  Recurrent outbreaks are variable and can occur as frequently as once per month or once per year.

HSV-1 Syndromes

HSV-1 can cause several neurological syndromes including encephalitis - infection of the brain tissue - that is characterized by fever, headache, seizures and impaired consciousness.  One third of cases occur in children and also in the elderly.  HSV-1 has also been associated with Bell’s Palsy.  HSV-1 can cause rare liver infection, especially in individuals taking steroids, living with HIV or cancer.

Oral Herpes Diagnosis

Diagnosis is generally based on an individual’s medical history, signs and symptoms, and lab work.  For patient’s presenting with active blisters or ulcers, samples can be from the ulcer and either cultured or used in a polymerase chain reaction (PCR) test to identify the herpes virus.  If no visible ulcers are present, but an individual has a history of oral ulcers or believes they’ve been exposed or infected, a blood test can be performed.  The CDC does not recommend screening for HSV-1 or-2 in young people without symptoms.  The blood test detects antibodies to HSV type 1 and 2; antibodies are not detectable the first few weeks after infection.  The blood test cannot differentiate oral from genital HSV-1 infection. However, a blood test can identify who is at risk of HSV infection, if the test comes back negative.

Is there a Cure or Treatment for Genital Herpes?

There is no cure for oral. herpes.  However, the infection can be managed with antiviral medication and self-care.

Antiviral medication valacyclovir (Valtrex) is taken by mouth in a pill form.  The dose and length of treatment depends upon whether an outbreak is a first occurrence or recurrent outbreak, as well as on medical history.

For recurrent outbreaks, there are two strategic ways individuals can use valacyclovir: episodic therapy and suppressive therapy.

Episodic therapy is taking antiviral medication only when outbreaks occur.  It can decrease the duration and severity of outbreaks if started within 72 hours of the onset of symptoms, including prodromal symptoms of tingling or pain before a blister occurs.  Episodic therapy does not reduce the frequency of outbreaks.

Suppressive therapy is taking antiviral medication every day to prevent outbreaks.  It decreases the frequency and duration of recurrences, and can reduce the risk of spreading oral herpes to someone else.  Suppressive therapy is recommended for individuals with frequent outbreaks, and or are in a relationship with a partner who does not have antibodies to HSV-1 or 2.

Key Points

  • Oral Herpes is caused the herpes simplex virus type 1 most often.
  • Symptoms of infection range from no symptoms to blisters around or in the mouth.
  • The first outbreak is usually the worst, and along with painful blisters may include systemic symptoms like fevers or muscle aches, sore throat; subsequent recurrent outbreaks tend to resolve sooner, be less severe.
  • Oral herpes is spread most easily when signs or symptoms of infection are present; HSV can also be spread when no symptoms are present due to invisible viral shedding.
  • Although it can’t be cured, oral herpes can be managed with antiviral medication taken either episodically or every day to decrease outbreak severity and speed up healing; suppressive therapy also has been shown to decrease spread to uninfected partners.


  1. Xu F, Lee FK, Morrow RA, Sternberg MR, Luther KE, Dubin G, Markowitz LE. Seroprevalence of herpes simplex virus type 1 in children in the United States. J Pediatr. 2007 Oct;151(4):374-7. doi: 10.1016/j.jpeds.2007.04.065. Epub 2007 Aug 10. PMID: 17889072.