Mouth Herpes (Oral) Virus, Recurrence, Spread, Treatment, Prevention

Oral herpes is a viral infection of the mouth. This condition is also referred to as mouth herpes, cold sores, fever blisters, recurrent herpetic stomatitis or acute herpetic gigivostomatitis. A typical feature of oral herpes is the appearance of small fluid-filled blisters (also known as vesicles) both inside and around the mouth. The vesicles usually appear on the palate (the roof of the mouth), inside surface of cheeks, gums, tongue and lips.

The vesicles may also appear on the skin around the mouth, nose and inside the nasal cavity. Oral herpes is not the same as oral canker sores, even though infection with Herpes simplex virus may be present alongside canker sores. The vesicles of canker sores are limited to the inside of the mouth, whereas lesions of oral herpes may be present both inside and outside the mouth.

The Oral Herpes Virus

Oral herpes is mainly caused by the Herpes simplex virus type 1 (commonly abbreviated as HSV-1). However, this disease may also be caused by Herpes simplex virus type 2 (abbreviated as HSV-2), which is mainly responsible for genital herpes. Genital herpes infection may be present in a few cases of oral herpes (caused by HSV-1).

Similarly, oral herpes infection may be present in a few cases of genital herpes (caused by HSV-2). Oral herpes can occur in individuals at any age. However, genital herpes is rare in children. If genital herpes is seen in children, sexual abuse needs to be investigated.

The first time a person gets infected with oral herpes is termed as primary infection. During the primary infection, an individual shows severe signs and symptoms such as fluid-filled vesicles, shallow ulcers, fever, swollen lymph nodes and headache. Despite aggressive treatment of the primary infection, oral herpes tends to recur. This recurrence is due to a reactivation of the Herpes simplex virus that lies dormant in the body.

The signs and symptoms of oral herpes seen during the reactivation phase are usually less severe than those seen during the primary infection phase. Oral herpes has a tendency to recur many times over the lifetime of a patient, with asymptomatic phases in between episodes of reactivation.

Symptoms of Oral Herpes

The signs and symptoms of oral herpes vary between the primary (first) infection and the recurring infection. The signs and symptoms of primary herpes infection are much more severe than that of recurrent herpes infections.

The following are some of the main signs and symptoms of primary oral herpes:

  • Sudden appearance of fluid-filled vesicles and ulcers inside the mouth and on the skin around the mouth.
  • Swollen lymph nodes in the neck region
  • Fever
  • Headache
  • Body pain
  • Loss of appetite

The signs and symptoms of primary oral herpes infection usually last for 10 to 14 days. The presence of vesicles and ulcers in the mouth makes eating and drinking very painful.

Read more on mouth ulcers.


Reactivation of the Herpes simplex virus leads to recurrence of oral herpes infection. The signs and symptoms of a recurrent herpes infection are not as severe as that of primary infection. Also, they usually last for only 4-6 days. By the 10th day after the recurrence of oral herpes, the signs and symptoms usually resolve completely. The following are some of the signs and symptoms of recurring oral herpes:

  • Appearance of solitary or small groups of vesicles (often on the lips)
  • A tingling, itching, or burning sensation preceding the appearance of vesicles

Causes of Oral Herpes

As mentioned previously, the predominant cause of oral herpes is the Herpes simplex virus type I (HSV-1). However, oral herpes can also be caused by the Herpes simplex virus type 2 (HSV-2). The signs and symptoms of oral herpes do not appear immediately after infection with the virus. Infection is followed by a viral incubation period that lasts anywhere from 2 days to 2 weeks.

After the incubation period, the first signs of oral herpes appear in the form of fluid-filled vesicles in the oral cavity. The vesicles result from localized inflammation caused by the virus. Ulcers form when the vesicles burst. The Herpes simplex virus also travels away from the site of infection and can remain hidden until reactivation. The exact cause of reactivation of the Herpes simplex virus is not understood. There are certain factors that seem to be associated with the reactivation of the virus: emotional stress, UV light, extreme temperatures, trauma, allergy, menstruation, pregnancy, immune suppression and certain dental procedures.

Reactivation of oral herpes can occur at any age. However, young adults are especially prone to reactivation of oral herpes, which usually presents as a mild cold sore. The HSV-1 virus can spread through direct contact with the saliva or respiratory droplets from an infected person. Infection is facilitated by breaks in the skin or mucus membranes. Use of contaminated kitchen utensils may also spread the virus.

It is possible for oral herpes to spread through sexual contact, especially when oral herpes is also accompanied by genital lesions. However, sexual contact is not a major route of transmission for HSV-1.

Read more on cold sores.

Diagnosis of Oral Herpes

A variety of viral infections can affect the oral cavity and the regions around the mouth. Examples include infections by Herpes zoster, measles virus, Epstein-Barr virus (commonly abbreviated as EBV), and cytomegalovirus (commonly abbreviated as CMV). Therefore, it is important to distinguish oral herpes from the other viral conditions.

Diagnosis of oral herpes requires consideration of the clinical history of the patient. Fluid from vesicles and tissue samples may be used for testing. Viral culture analysis and blood tests to identify the presence of HSV-1 or HSV-2 may also be done.

Treatment of Oral Herpes

Treatment for oral herpes must be initiated as soon as possible (even before the appearance of visible lesions). Despite aggressive treatment, however, recurrence may still occur. Both topical and oral medications are used to treat oral herpes.

  • Topical medicines: Topical antiviral ointments, creams, or solutions containing penciclovir or docosanol may be prescribed to treat oral herpes as soon as possible. Treatment using these topical medicines may begin as soon as the pre-lesion symptoms of itching, burning and tingling sensations appear. For pain relief, your doctor may prescribe a mouthwash with lidocaine or a topical anesthetic containing benzocaine.
  • Oral medicines: Oral antiviral medicines are only prescribed in severe cases. The oral medications usually contain acyclovir, famciclovir or valacylovir. If viral resistance to acyclovir develops, then foscamet may be used. However, use of these agents is rare in the treatment of oral herpes.

Prevention of Oral Herpes

It is difficult to avoid primary infection with HSV-1 and a recurrence of oral herpes. Most of the measures used to control the recurrence and spread of oral herpes are focused on personal hygiene and avoidance of triggers. The following preventive measures can be taken to control the recurrence and spread of oral herpes:

  • Avoid kissing or sharing of kitchen utensils with an infected person
  • Avoid sharing personal clothing with an infected individual
  • Wash hands after contact with a person with cold sores
  • Avoid direct physical contact with an infected person
  • Avoid the factors that are known to trigger recurrence of oral herpes

More Related Topics