Cold sores are a common viral skin infection primarily caused by the herpes simplex virus (HSV). This virus is divided into two types, HSV-1 and HSV-2, with over 90% of cold sore cases caused by HSV-1. Once infected, the virus remains dormant in nerve ganglia for life and may reactivate under certain conditions, such as immune suppression or environmental stimuli. Although cold sores are usually not life-threatening, they can impact patients' quality of life, including social discomfort and physical discomfort.
Transmission mainly occurs through direct contact with infected areas, such as kissing, sharing personal items, or contact with active lesions. After initial infection, the virus may cause an acute outbreak, but some individuals may remain asymptomatic. Recurrent outbreaks are characterized by recurrent blisters around the mouth or face, often accompanied by burning or tingling sensations. Modern medicine has developed various treatments, including antiviral medications and topical care measures, but the virus cannot currently be eradicated completely.
The development of cold sores is closely related to infection with herpes simplex virus (HSV). HSV-1 is mainly transmitted through contact, such as direct contact with lesions or sharing utensils. Primary infection may cause initial outbreaks with symptoms like fever, lymphadenopathy, and oral ulcers. HSV-2, although primarily causing genital infections, can also cause perioral outbreaks under certain circumstances.
Risk factors include immune system suppression, such as in cancer patients undergoing chemotherapy or HIV-infected individuals, which often leads to higher recurrence frequency and severity. Long-term stress, ultraviolet exposure (e.g., sunbathing), hormonal changes (e.g., menstrual cycle), and fatigue can trigger virus activation. Additionally, individual viral load and the latent state in nerve ganglia influence recurrence frequency and severity.
Symptoms of cold sores typically develop in stages. The first stage involves prodromal symptoms, where patients may feel burning, tingling, or swelling at the site, usually appearing 1-2 days before blisters form. The second stage involves the formation of clusters of small blisters, often grouped, located around the corners of the mouth, nostrils, or chin.
After the blisters rupture, shallow ulcers form, which may crust over. This process usually takes 7-10 days to heal. The degree of itching and pain varies among individuals; some may also experience regional lymphadenopathy or fever. Recurrent episodes tend to be milder than initial infections but can cause long-term skin damage with repeated outbreaks.
Diagnosis of cold sores is usually based on clinical presentation. Doctors observe the typical clustering of blisters and the location of onset, and inquire about the patient's history, such as previous similar symptoms or contact with infected individuals. Laboratory tests may be needed for confirmation or atypical cases.
Common diagnostic methods include viral culture, where blister fluid is collected for culture to confirm the presence of the virus. PCR nucleic acid testing can quickly identify viral DNA and is especially valuable in early stages before blisters fully develop. Immunofluorescence tests detect antibody responses, helping distinguish primary infection from recurrent episodes.
For immunocompromised patients or cases with severe symptoms, more in-depth testing may be recommended. For example, Tzanck smear examination can reveal cytological changes, or imaging studies may be used to rule out other infectious diseases. These additional tests can improve diagnostic accuracy, but most cases are diagnosed based on clinical observation alone.
The goal of treatment is to shorten the disease course, relieve symptoms, and prevent complications. Antiviral drugs such as acyclovir are first-line treatments, available orally or topically, which inhibit viral replication and accelerate healing. Newer drugs like valacyclovir have high bioavailability and are suitable for severe or frequent recurrences.
Topical care measures include using anesthetic ointments to relieve pain and keeping the lesion clean to prevent bacterial infection. Cold compresses or anti-inflammatory ointments can reduce redness and swelling, while vitamin E ointments help repair damaged skin. In cases of secondary bacterial infection, antibiotics may be prescribed topically or orally for a short duration.
Patients with frequent recurrences (more than 6 times per year) may consider long-term low-dose antiviral therapy for prevention. Such treatment should be supervised by a physician to avoid drug resistance. Applying antiviral creams at prodromal stages (e.g., tingling sensation) can also effectively suppress outbreaks.
The key to preventing the spread of cold sores is avoiding direct contact with active lesions. Infected individuals should avoid kissing, sharing utensils, or shaving tools during outbreaks, and keep lesions dry and clean. Thorough handwashing after contact with lesions can significantly reduce transmission risk. High-risk groups, such as immunocompromised individuals, should avoid contact with known sources of infection.
Daily protective measures include using lip balms with sun protection factor (SPF), as sunlight exposure is a common trigger. Strengthening immunity through regular exercise, adequate sleep, and a balanced diet can reduce recurrence rates. Although the herpes simplex virus vaccine is not yet widely available, research is ongoing.
In households, personal hygiene items such as towels and toothbrushes should be used separately. During outbreaks, avoid contact with infants or immunocompromised individuals. In public places, avoid contact with suspicious skin lesions and maintain hand hygiene.
If you experience unexplained perioral blisters, worsening symptoms, or high fever, seek medical attention immediately. Even immunocompromised patients with mild symptoms should consult early. If blisters become infected, leading to cellulitis, involve the eyes, or symptoms persist beyond two weeks, professional evaluation is necessary.
Special situations include first outbreaks with severe pain, symptoms affecting eating or breathing, or infections during pregnancy. These cases may require medication or hospitalization to prevent serious complications or vertical transmission to the fetus. The doctor may adjust treatment based on medical history and laboratory results.
If any of the following occur, consider it a medical emergency:
Prompt medical attention can effectively prevent scarring and secondary bacterial infections, especially in cases with high risk of facial nerve damage.
During outbreaks, topical antiviral ointments (such as acyclovir cream) can shorten the course and reduce pain. Cold compresses or clean cotton pads applied gently to the lesion can also relieve swelling. Avoid scratching or rubbing the affected area. If pain is severe, short-term use of painkillers is recommended, but should be used under medical supervision.
Is herpes labialis contagious? How is it transmitted?Herpes labialis caused by herpes simplex virus (HSV-1) is contagious. It mainly spreads through contact, such as touching the lesion secretions, sharing utensils, or kissing. The virus is most contagious during the blister rupture stage, so avoid contact until scabs fall off.
How can recurrent herpes labialis be prevented?Triggers include stress, fatigue, or UV exposure. Daily measures include maintaining regular routines, supplementing with vitamin B complex and vitamin C, and using lip balms with SPF. For frequent outbreaks, doctors may prescribe low-dose antiviral medication for ongoing prevention.
What precautions should be taken if herpes labialis occurs during pregnancy?During pregnancy, self-medicating with ointments or drugs is not recommended. Seek medical evaluation promptly. The doctor will choose the safest treatment options based on gestational age and severity. During outbreaks, avoid contact with the fetus and maintain good personal hygiene to prevent vertical transmission.
Is it true that using toothpaste or alcohol can treat herpes labialis?This is not accurate. Common toothpaste or alcohol may irritate the skin and worsen redness and pain. Proper treatment involves cleaning the lesion and applying prescribed antiviral ointments, keeping the area dry. If symptoms worsen after using non-medical products, stop and consult a healthcare professional.
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