Cold sores – causes, symptoms and other risk factors

Cold sores

Cold sores are small blisters which are developing around your mouth or on your lips. The reason why you have cold sores is the herpes simplex virus. In the most cases this kind of virus goes better on its own in a period of seven to ten days without any kind of treatment. In many cases when people get this disease in the first stages of this disease they do not feel any kind of symptom. As the times are going on, they can notice that there is an outbreak of the cold sores. In the beginning of this condition you can feel a burning, itching or tingling sensation around the mouth. In this period you can notice that the sores are small and also they are full of fluid. In the most cases these sores are appearing on the edges of your lower lip. If you had suffered from cold sores in your past, then you should know that they can return again. Also you know the way how they outbreak. If you do not know if you have a sore or you have severe cold sores which are not only on your mouth but also they are spreading further than just your lips, then you must visit your doctor as soon as possible. Also if you have noticed that the sores have not improved in a period of seven to ten days, then you must visit your doctor as soon as possible. You should talk with your doctor about the remedies which you should take if you suffer from cold sores.

Symptoms of cold sores

The primary infection of the cold sores is the herpes simplex virus. In the beginning when you are infected with this kind of virus, then you usually do not feel any kind of symptom. [1] As time passes by, you can see outbreak of cold sores. Also there are some cases when you have recurrent infection which means that you will have cold sores again. But if this virus has not caused you any kind of symptom, then they usually are severe.

Cold sorescold sores symptoms and causes

Causes of cold sores: The herpes simplex virus type one (HSV – 1) is the cause for the cold sores. In the early childhood children have the biggest chances to get cold sores because in this period this virus can be easily passed on. When someone of your family or some friend has cold sores and it kisses your child, then your child can get sores. This kind of virus passes throughout your skin and travels to your nerves where is dormant (which means it lies inactive) until some factor triggers it in some later period.

Cold sores triggers: There are some factors which can trigger the outbreak of cold sores such as

  • Strong sunlight [2]
  • Menstruation (periods) [2]
  • An injury to the affected area
  • Tiredness and fatigue [3]
  • Emotional upset or psychological stress [3]
  • Having a high temperature (fever)
  • Having another infection such as a respiratory tract infection

But also there are some cases when there is not known trigger for the outbreak of the cold sores.

Complications of the cold sores: In the most cases this condition is mild, but also there are situations where it can cause complications. People who use chemotherapy [4] or who have weak immune system, have increased chances of getting complications of sores. They can become dehydrated because in some cases when you drink fluids, then this process can painful. This is a case in young children who can easily become dehydrated. [5] Also this kind of virus can spread to other parts of our bodies. You should treat the sores because it can cause the cornea which means that your eyes can become infected which in some cases can lead to blindness. If you have unhealed cold sores, then you should not touch your eyes. Also this condition can lead to herpetic keratoconjuctivitis (swelling and inflammation of your eyes), herpetic whitlow (cold sores on and around your fingers) or skin infections (graze, cut, eczema). [6]

Herpes simplex virus type 2: Also there are some cases when sores can be caused by HSV – 2 (herpes simplex virus type 2). HSV – 2 leads to genital herpes. If you have oral sex with a woman or a man who has genital herpes, then you have increased chances of getting cold sores. When you have this kind of cold sores, then you can notice painful blisters in the surrounding area of your genitals or they develop on your genitals.


[1] Cornell University. Discovery reveals mechanism that turns herpes virus on and off. ScienceDaily. 2019. Retrieved from

[2] NHS UK. Cold sores. Retrieved from

[3] University of Virginia Health System. Cold sores: Discovery reveals how stress, illness and even sunburn trigger flareups. Science Daily. 2021. Retrieved from

[4] Kanai R, Wakimoto H, Cheema T, Rabkin SD. Oncolytic herpes simplex virus vectors and chemotherapy: are combinatorial strategies more effective for cancer? Future Oncology. 2010;6(4):619–34.

[5] Usatine RP, Tinitigan R. Nongenital herpes simplex virus. American Family Physician. 2010;82(9):1075-82. Retrieved from

[6] Azher TN, Yin XT, Tajfirouz D, et al. Herpes simplex keratitis: challenges in diagnosis and clinical management. Clinical Ophthalmology. 2017;11:185–91. doi: 10.2147/OPTH.S80475


Please enter your comment!
Please enter your name here

This site uses Akismet to reduce spam. Learn how your comment data is processed.