Coldsore symptoms
Cold sores are grouped blisters caused by herpes simplex virus, usually appearing on or around the lip and healing in stages.
The short answer
Cold sores are clusters of fluid-filled blisters caused by herpes simplex virus, commonly on the lip border or nearby skin, followed by crusting and healing.
Why can cold sores return after the first infection?
The virus remains in nerve tissue after the first infection and can reactivate in the skin supplied by that nerve. Tingling or burning may come first, followed by small blisters that break, weep, crust, and resolve.
How can you limit spreading a cold sore to others?
Keep the area clean, avoid picking the crust, wash hands after touching it, and avoid kissing or sharing cups, utensils, lip products, or oral contact while lesions are present. A clinician can discuss an antiviral medicine early in an episode when appropriate.
When does a cold sore need urgent dental assessment?
Seek medical or dental assessment for an eye-area lesion, severe or widespread sores, difficulty drinking, frequent recurrences, an episode that does not heal, or a weakened immune system. A new mouth ulcer without typical blisters may have another cause.
What should the dentist check when a lip lesion appears?
Is the lesion on the lip border or inside the mouth? Did tingling precede grouped blisters? Could another condition explain it, and would early antiviral treatment be appropriate?
Frequently asked questions
Are cold sores the same as canker sores?
No. Cold sores usually form grouped blisters on or around the lip, while canker sores are ulcers inside the mouth.
Can a cold sore spread to the eye?
Yes. Avoid touching the lesion and then the eye, and seek prompt care for eye pain, redness, or a lesion near the eye.
Who wrote this page
This library is published by Dental Nation, a licensed dental group practising in the United Arab Emirates. Pages are written and overseen by the same clinical team that treats patients in our clinics, and are held to a fixed editorial standard for safety and accuracy.
This page is patient education, not medical advice, and cannot replace an examination. Anything urgent — facial swelling, trauma, uncontrolled bleeding or severe pain — needs a dentist or emergency care now.