Herpes labialis, also known as oral herpes, is an infection of the mouth area caused by the herpes simplex virus type 1 (HSV-1) . It is characterized by small, painful blisters that develop on the lips, gums, or throat. The virus is usually transmitted through saliva, and most people in the United States are infected with this virus by age 20. After the first infection, the virus goes to sleep in the nerve tissues in the face and can later reactivate, causing cold sores.

Symptoms of oral herpes include:

• Small, painful blisters commonly called cold sores or fever blisters
• Swollen lymph nodes and headache during the initial infection

Oral herpes is often confused with many other infections and can only be confirmed with a virus culture called PCR, blood test, or biopsy. PCR is the preferred test for diagnosing herpes infections. The best treatment for oral herpes is antiviral oral medication, and symptomatic treatment may include antiviral ointment, over-the-counter topical anesthetics, or over-the-counter anti-inflammatory agents.

To reduce the risk of spreading herpes simplex viruses, which can cause cold sores and genital herpes, it is important to avoid intimate or personal contact with someone who is infected when lesions are present.