Woman in her 50s touching her lips in bathroom

Herpes simplex 1: What you should know

By Ruben J. Rucoba, MD May 18, 2022 • 6 min


Though they are extremely common, cold sores are often misunderstood. Are they really a herpes infection? Are they a sexually transmitted disease? Can they be treated? Those with cold sores have lots of questions about herpes simplex 1, and we have the answers.

What’s herpes?

Herpes is a family of viruses, some of which are quite common. For example, herpes zoster, the virus that causes chickenpox and shingles, is a herpes virus. Others include herpes simplex virus, types 1 and 2.

  • Herpes simplex 1 (HSV-1): Most commonly associated with infections in the mouth, this virus can also cause genital infections.

  • Herpes simplex 2 (HSV-2): Transmitted through sexual contact, this virus is most commonly associated with genital herpes infections. However, it can also cause some infections in and around the mouth.

Once someone has herpes, the virus stays with them forever. A person with herpes won’t always have symptoms, and some may never experience any symptoms at all. However, after an initial outbreak, people often get recurrences of cold sores from time to time when the virus is reactivated.

Oral herpes

Usually caused by HSV-1, people may refer to oral herpes in a number of ways including:

  • Cold sore

  • Fever blister on the lip

  • Mouth herpes

  • Stomatitis (meaning "infection of the mouth")

When someone is infected with HSV-1, their symptoms usually follow a predictable sequence:

  • Initial feelings of redness, itching, swelling, heat and pain in the area in which the lesions will appear

  • Painful, fluid-filled blisters, which are highly contagious, on the lips or under the nose

  • The blisters "pop" open and leak fluid, then form sores

  • After four to six days, the sores crust over and heal

How do you get oral herpes?

HSV-1 is transmitted by saliva. The virus can spread by kissing or touching someone with cold sores, or by sharing utensils, cups, straws, towels or other objects with someone with cold sores. Many people initially get infected in childhood.

Once infected, the virus doesn't go away but instead lies dormant in nerve cells. Some people never get any symptoms again from the virus, while others have recurrences. Several circumstances can trigger the virus to recur. These include:

  • Cold weather

  • Fever

  • Other infections

  • Long or intense exposure to sunlight

  • Menstrual periods

  • Physical injury

Recurrences are usually more common in the first year after the initial outbreak. After that, they tend to be less frequent and less severe.

How is oral herpes treated?

Oral herpes usually goes away in one to two weeks, but there is no true herpes cure. However, many treatments are used to help with the pain of cold sores and speed up the healing of lesions. These include:

  • Cold compresses for pain

  • Eating and drinking cold foods

To help prevent infection and spread of oral herpes, follow these steps:

  • Avoid close contact with anyone with herpes sores

  • Avoid kissing anyone if you have a cold sore

  • Avoid oral sex if you or your partner have HSV-1, which can be spread to the genitals

  • Keep your drinking glasses, utensils, towels and washcloths separate from those used by others

  • Wash bedding and towels in boiling hot water after each use

  • Wash your hands well, especially after touching cold sores

  • Use a lip balm with SPF when going outdoors

Although they don't signify serious health issues, the mouth lesions associated with oral herpes can be painful and unsightly. If you are having recurrent cold sores, see your healthcare provider to discuss possible treatment options.

Published May 2022.

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