What is a cold sore?

Cold sores are an infection that can occur in the lips, gums or mouth in general. It is produced by the herpes simplex virus. The lesion is usually vesiculous with small blisters. There are two strains of this virus, VSH-1, which causes cold sores and VSH-2, which causes genital herpes.

According to information in BMJ Clinical Evidence, between 20% and 40% of adults are affected at some time. However, primary infection usually occurs in childhood and it is believed that the virus remains dormant in the trigeminal ganglion.

Causes of cold sores

After overcoming the symptoms of the first infection, the virus is lethargic in the body, when the virus is activated again, it produces again those vesicular lesions, called fever.

The spread of this virus is very easy during the presence of lesions, only physical contact with another person is necessary for contagion to occur. It is not a hereditary virus.

The use of objects that have been in contact with the lesion can also cause contagion., such as razors, towels, lipstick, etc. According to the WHO, about 3700 million people aged below 50 are infected worldwide.

Often, primary herpes infection occurs in childhood. However, the virus remains latent and infection can be repeated before certain stimuli.

Risk factor's

There are factors that some people have and that favor the appearance of this virus, such as:

  • People with depressed immune system.
  • Patients with immune diseases, such as HIV / AIDS.
  • People with severe burns.
  • Patients under chemotherapy treatment.
  • Those who are under medication treatment to avoid transplant rejection.

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Symptoms of cold sores

They can be mild or severe, depending on each person, they can even become asymptomatic. The first symptoms usually appear after 1-2 weeks after infection and usually last between 7 and 15 days.

The most common symptoms are:

  • Itching in the area of ​​the lesion.
  • Local heat.
  • Appearance of blisters: usually appear at the junction between the lip and the skin
  • Tingling in the area near the lips: commonly before the appearance of the lesion.
  • Swelling of the lips
  • Suppuration and scabs: the blisters can join and explode, secreting fluids and forming a subsequent scab.

You can also see discomfort in the throat or swollen lymph nodes. The areas where it can commonly appear are:

  • Throat.
  • Lips.
  • Gums
  • Mouth.
  • Nostrils.
To combat cold sores, antiviral creams or drugs can be used systemically. Symptoms can last between 7 and 15 days.

Why do they occur?

After the first infection of the virus, it can reappear for different reasons, for example:

  • Descent of defenses.
  • Stress.
  • Sunbathing in excess.
  • Menstruation.
  • Hormonal changes.
  • Fever.

Tests to detect it

When there is a case of very repetitive herpes, or the lesions are larger than what is considered normal, different tests are usually done. The most frequent is performing a virological culture of the vesicles in the initial phase of the disease.

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Cold sore treatment

In order to treat this pathology, two types of treatments can be used. Topical treatment, which is based on the application of an antiviral cream in the area. This treatment is effective if it begins to be applied from the first discomforts.

If the administration of drugs at the systemic level is necessary, the same antivirals are used but administered in tablets. The commonly used drugs are:

  • Acyclovir
  • Pharmaciclovir
  • Valacyclovir.

Treatments such as pain relievers can be used to prevent discomfort. Apart from the use of drugs, There are also tips that can improve or avoid them:

  • Avoid sharing utensils with people who present it.
  • Use lip balm to prevent them from drying out.
  • Eat a healthy diet.
  • Avoid kisses.


Cold sores are a highly contagious infection caused by the herpes simplex virus. Although primary infection occurs in childhood, it can reappear in adulthood due to various factors. For its control it is necessary to use antivirals.