Recurring Lip Blisters? Why Cold Sores Occur

In the winter, when the cold wind becomes harsh, the body’s immunity is relatively easy to weaken due to the rapid drop in temperature and dry air. During this period, many people complain of symptoms such as itching or tingling around the lips and the formation of small blisters. This is typically caused by a virus that has been dormant in the body becoming active when immunity drops. Today, we will look into why cold sores, the unwelcome guests of winter, occur and how to prevent them in daily life.

Cold Sores, Why Do They Occur?

Lip blisters can occur for various reasons, but the most common type observed clinically is cold sores (herpes labialis). Cold sores are caused by Herpes Simplex Virus Type 1 (HSV-1) and are known to be one of the most common viral infections in humans. According to the Korea Disease Control and Prevention Agency (KDCA), when this virus first infects, it forms blisters in the mouth or around the lips; even after the symptoms disappear, it is not completely eliminated but remains dormant in the body. The virus then hides in a collection of nerve cells called the ‘Trigeminal ganglion’ and maintains an inactive state in the form of DNA. This dormant virus reactivates when the immune system is temporarily weakened. Especially when the temperature drops sharply like in winter, or when the body’s balance is disrupted due to stress from excessive work, lack of sleep, or UV exposure, the virus moves along the nerves to the skin, causing an inflammatory response and the lip blisters we commonly see. According to data from the Korean Dermatological Association, it is a very common virus, with about 60–90% of the adult population having experienced HSV-1 infection, but the frequency and intensity of actual symptom recurrence vary greatly depending on an individual’s immune status.

Picking at Cold Sores Leads to Secondary Infection

Cold sores generally progress through four stages. The first is the ‘prodromal stage,’ where there are no visible blisters yet, but the area around the lips feels burning, itchy, or tingly. Using antiviral agents quickly during this period helps shorten the overall treatment duration. In the second ‘vesicular stage,’ small, millet-like blisters appear in clusters. In the third ‘erosive stage’ (ulcer stage), the blisters burst, oozing fluid and causing the skin to become raw. This is the stage that requires the most caution. If you touch the wound with your hands, the virus can spread to your fingers or eyes, potentially causing ocular herpes. If a secondary infection by bacteria such as Staphylococcus aureus occurs, the risk of scarring increases. Later, in the ‘healing stage,’ a scab forms and gradually heals. Forcing the scab off during this process should be avoided as it delays recovery and can leave pigmentation or scars. It is important to note that cold sores may not be limited to the lips. In cases of severely weakened immunity, although rare, it has been reported to progress to meningitis or encephalitis. Furthermore, if a patient with atopic dermatitis contracts cold sores and it becomes serious, it can worsen into a severe complication called ‘Eczema herpeticum,’ requiring even more careful management.

Characteristics and Recommended Actions by Cold Sore Progression Stage

The Key to Preventing Recurrence: Immunity Management

The most fundamental reason cold sores recur lies not in the virus itself, but in an immune state that fails to suppress it. Since Herpes Simplex Virus (HSV-1) does not completely disappear from the body once infected and remains dormant in the ganglia, whether it recurs depends on how stably the immune system is maintained rather than the presence of the virus. In particular, the decline in the function of T cells and NK cells (natural killer cells), which regulate viral infections, is known to be closely related to viral infections like cold sore recurrence. Chronic fatigue, lack of sleep, stress, and nutritional imbalances lower the activity of these immune cells, creating an environment for the dormant virus to reactivate. In winter, the immune balance can be easily disrupted due to vitamin D deficiency from reduced sunlight, increased indoor activities, and dry environments.

1. KAIST. (2022, June 8). Discovery of new immune T cells that break existing concepts [News]. Korea Advanced Institute of Science and Technology. https://zrr.kr/qByQOh

Therefore, to prevent cold sores, it is important to maintain a stable immune system through lifestyle management and systematic health checks, rather than relying solely on drug treatment when symptoms appear. Sufficient sleep, regular meals, balanced intake of protein, vitamins, and minerals, and stress management are all factors that practically help suppress viral reactivation. The importance of such immunity management is increasingly emphasized in recent medical fields, and some medical institutions are implementing prevention-oriented treatments that evaluate immune status through a functional medicine approach and manage individual vulnerability factors. Chaum Power Aging Clinic is one such medical institution known for prevention treatment based on immunity management, providing immune status checks and overall lifestyle and nutritional management for patients suffering from recurring cold sores or chronic fatigue.

Recurring lip blisters are not just a simple skin problem, but may be an immune warning signal from our body. If frequent recurrences continue, checking your body’s resilience and defense system rather than just looking at the symptoms is the most realistic starting point for preventing cold sores. We hope you spend a healthy and warm winter through immunity management.

Reference: Korea Disease Control and Prevention Agency (KDCA)

https://health.kdca.go.kr/healthinfo/biz/health/ntcnInfo/healthSourc/thtimtCntnts/thtimtCntntsView.do?thtimt_cntnts_sn=64

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