Quick read
Key points
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Cold sores are small, painful blisters that typically appear around the mouth or lips, caused by the herpes simplex virus. Once someone is infected, the virus stays dormant in the body and can reactivate periodically, often triggered by stress, illness, sunlight, or a weakened immune system.
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Topic-specific prevention and risk reduction will be added during the article-specific evidence audit.
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Cold sores are severe, very frequent, or not healing within two weeks
01 · Know
What is Cold Sores?
Cold sores are small, painful blisters that typically appear around the mouth or lips, caused by the herpes simplex virus. Once someone is infected, the virus stays dormant in the body and can reactivate periodically, often triggered by stress, illness, sunlight, or a weakened immune system.
Cold sores usually heal on their own within one to two weeks. While there's no cure for the underlying virus, antiviral creams can help speed healing and reduce discomfort, particularly if started as soon as the first tingling sensation is noticed.
02 · Understand
Clinical context
Treatment works best at the very first sign
Antiviral cream is most effective when applied at the very first tingling or itching sensation, before the blister has even appeared — waiting until the sore is fully formed reduces how much difference treatment can make.
03 · Act
When to See a Doctor
- 1Cold sores are severe, very frequent, or not healing within two weeks
- 2You have a weakened immune system and develop a cold sore
- 3The cold sore spreads near the eye, which needs prompt assessment
- 4You'd like to discuss prescription antiviral treatment for frequent outbreaks
04 · Prevent & manage
Practical steps
Cold Sores Are Contagious — Avoid Close Contact While Active
Cold sores are contagious from the first tingling sensation until fully healed — avoid kissing, sharing utensils or towels, and be especially careful around newborns during this time.
- 1Apply antiviral cream at the first sign of tingling.This is when treatment is most effective at reducing severity and healing time.
- 2Avoid touching the cold sore.This reduces the risk of spreading the virus to other parts of your body or to others.
- 3Use a separate towel and avoid sharing lip products.This helps prevent spreading the virus to others in your household.
- 4Protect your lips from sun exposure.Sunlight is a common trigger for cold sore outbreaks — using a lip balm with SPF can help.
- 5Manage stress and get adequate rest.These can help reduce the frequency of outbreaks for some people.
Evidence
References
BarnMD Health Intelligence uses authoritative and clinically relevant sources appropriate to the topic. References are shown so readers can inspect the evidence directly.
- NHS: Cold sores ↗
- HSE: Cold sores ↗
Medical information notice
Health education, not individual medical advice
BarnMD Health Library provides general health education for public health literacy. Reading this article does not establish a doctor-patient relationship and this information is not a diagnosis, prescription, or personalised treatment plan. If you have symptoms or concerns about your health, seek appropriate advice from a qualified healthcare professional. If you develop emergency warning signs, seek urgent or emergency medical attention.
BarnMD Bottom Line
Cold sores are common and usually heal within one to two weeks, especially with prompt antiviral treatment at the first sign.
Applying antiviral cream at the very first tingling sensation, before the blister appears, gives the best results.