Cold sores (herpes simplex)

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Cold sores (herpes simplex)


​Cold sores are a common infection caused by the herpes simplex virus, and they usually appear around the area of the mouth, lips or face. The symptoms are easy to identify and cold sores usually heal without treatment. You can try topical remedies to reduce your symptoms.

Cold sores spread from person to person by close contact, such as kissing. The majority of middle-aged Finns are carriers of the herpes virus. The primary infection usually shows no symptoms, but the virus lies dormant in the body and may reactivate for various reasons. Most often recurrence is triggered by a cold, exposure to sunlight, stress, menstrual periods or procedures in the mouth area. Every third infected person will experience at least one recurrence of the infection in their lifetime. Few people may have recurrent episodes even once a month.


​Cold sores tend to appear at the same spot each time. The first symptoms include numbness, burning and itching of skin. Usually, by the following day small blisters, typical of herpes infection, appear. Small fluid-filled blisters typically erupt on and around the lips, nostrils or anywhere on the face. Sometimes herpes can spread also to fingers, genitals or buttocks. Recurrent episodes do not necessarily have any visible symptoms. Once the blisters burst, they form painful ulcers. Cold sores are contagious as long as there blisters or scabs are visible on the skin or mucous membranes​.


​Blisters and scabs usually heal on their own, and if the symptoms are mild, no treatment is necessary. Herpes can spread and therefore the blisters and scabs should not be touched, and the possibility of contraction in contact sports (martial arts, for instance) should be taken into consideration. You can try ointments available at pharmacies without a prescription to reduce your symptoms, however, there has not been much evidence to confirm their effect. Pharmacy staff will help you select the right product, if necessary.​

Healing may take from a few days to 3-4 weeks.​

When should you seek medical advice?

​You should seek medical advice, if

  • your symptoms are severe (a temperature and feeling ill) and blisters are widespread.
  • in addition to herpes symptoms you experience symptoms of a corneal infection (pain, discharge, redness, feeling of foreign body in the eye, painful sensitivity to light or decreased vision).
  • herpes causes facial paralysis Symptoms of facial paralysis include pain in or behind the ear, drooping of the mouth, inability to frown, close eyes or whistle, sound hypersensitivity and dryness of the eye on the affected side.
  • herpes causes a lymphatic infection (a red streak radiating from the hand toward armpit, or from the groin toward the nearest lymph gland, no typical herpes blisters).
  • there are more than 6 recurrent herpes outbreaks per year.

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The producers of the instruction

​​​​​Emergency care professionals have produced the instruction in collaboration with Terveyskirjasto.​


Updated  1.5.2021