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Cold sores vs. herpes: Are they the same?

Medically reviewed by Sally Chao, MD. Last updated on Sep 21, 2023.

Official answer


Yes, they are similar. Cold sores are usually caused by herpes simplex virus type 1 (HSV-1) and are also known as oral herpes or fever blisters. But there are other types of herpes viruses. The herpes simplex virus type 2 (HSV-2) usually causes genital herpes, but cases of cold sores caused by the HSV-2 virus are becoming more common.

The HSV-1 virus that causes cold sores is very common, and close to 70% of people under the age of 50 have been infected with HSV-1. It can be passed from person to person through kissing, touching or sharing items that touch the mouth area.

Most infections start in childhood, and most infections do not cause any symptoms. Once a person is infected with HSV-1, the virus lives in nerve cells and may become active if there is stress, illness or sun exposure. Cold sores usually form on the outside of your mouth or lips. Less commonly, they may form on other areas of the face.

You might develop a cold sore about 2 to 20 days after you are exposed to someone with HSV-1. Before HSV-1 brings on a cold sore, there may be tingling, itching or burning. One or more fluid-filled cold sore blisters may form. They typically go from painful blisters to oozing sores with crusting lasting 7 to 10 days. In some cases, there may also be a fever or muscle aches. The active infection usually clears in 2 to 3 weeks.

Cold sores may go away without treatment, or they may be treated with an antiviral medication prescribed by your health care provider. Prescription medications can help reduce symptoms and reduce recurrence. Over-the-counter medications that numb the cold sores, or placing ice on cold sores, can help relieve the symptoms.

Cold sores are different from canker sores, which form inside the lips or inside the mouth. Canker sores are not caused by a virus, and they are not contagious. Canker sores are shallow gray ulcers with a red outer border. The cause of canker sores is not completely understood. They may be an immune response to bacteria or viruses in the mouth.

Canker sores will go away without treatment.

  1. American Academy of Dermatology (AAD). Herpes simplex. 2021. Available at: [Accessed September 1, 2021].
  2. World Health Organization (WHO). Herpes simplex Virus. May 2020. Available at: [Accessed September 1, 2021].
  3. American Dental Association (ADA). Canker Sores. Available at: [Accessed September 1, 2021].

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