What triggers a cold sore?

What triggers a cold sore?

After you have been infected with HSV-1, the virus never goes away. It remains dormant (inactive) in a group of nerve cells in your face called the trigeminal ganglion.

When the virus is triggered, or activated, it “wakes up” and travels through your nerves to your lips, where a cold sore develops. After an outbreak, the virus goes back to sleep in your body.

What triggers a cold sore in one person might not cause an outbreak in another person. Some people with HSV-1 never develop a cold sore.

A cold sore can be activated by a variety of factors, including:

• Hormonal changes during menstruation or pregnancy
• Sunburn
• Extreme temperatures (hot or cold)
• Stress (physical or emotional)
• Fatigue
• Fever and illness, such as cold or flu
• Damaged, dry or cracked lips