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What Are the Symptoms of a Cold Sore?

Cold sores, which are caused by the herpes virus, are associated with symptoms such as pain, tingling, itching, and oozing. Sometimes these symptoms begin shortly before the blisters appear. Cold sores develop as small, fluid-filled blisters around the mouth.

What Cold Sores Look Like

Cold sores usually appear on or around the lips. Most cold sores are limited to one side of the mouth, and they typically break out along the outside edges of the lips. In some cases, the sores can spread to other areas, such as around the nose or on the cheeks. Children ages 5 and under might get cold sores inside their mouths.

The small sores often develop in a cluster and then merge into a large blister. If the blister bursts, it leaves a shallow, open sore that oozes fluid and then crusts over. Although the virus that causes cold sores can spread at any time, it’s most contagious when someone has an open sore.

Other Cold Sore Symptoms

Besides the development of small blisters, cold sores might feel painful, itchy, or tingly. This sensation can begin in the hours or days leading up to a cold sore breakout.

During their first outbreak, some people also experience symptoms such as:

  • Sore throat
  • Headache
  • Fever
  • Muscle aches
  • Swollen lymph nodes
  • Painful and/or eroded gums

People can apply over-the-counter medications, such as ointments with numbing agents, to help alleviate the symptoms.

Cold Sore Recurrence

Most cold sores clear up without any treatment, but the virus never goes away. Instead, it lies dormant in the body and can cause more outbreaks in the future.

Certain situations or environments can trigger cold sore recurrence, such as:

  • Fatigue
  • Stress
  • Fevers or other viral infections
  • Hormonal changes, including during menstruation or pregnancy
  • Immune system changes or deficiencies
  • Exposure to wind, sunlight, or ultraviolet lamps
  • Dental treatments
  • Food allergies

Because cold sores are caused by the herpes virus, antiviral medications can reduce the frequency and severity of outbreaks.

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