Cold sores are small blisters that develop on the lips or around the mouth, caused by the herpes simplex virus (HSV) . HSV-1 usually causes cold sores, but HSV-2 can also be the cause of genital herpes. Cold sores are highly contagious and can be easily passed from person to person by close direct contact, such as kissing or sharing eating utensils or towels. The virus can spread even if you dont see the sores, and many people who are infected with the virus that causes cold sores never develop symptoms. Once youve had a herpes infection, the virus can hide in nerve cells in the skin and may cause another cold sore at the same place as before.
Cold sore outbreaks are often triggered by exposure to hot sun, cold wind, a cold or other illness, a weak immune system, or even stress. Hormonal changes during menstruation or pregnancy, fever, fatigue, and being in the sun or wind can also trigger a cold sore outbreak. Damaged, dry, or cracked lips can also be a trigger.
In summary, cold sores are caused by the herpes simplex virus, and outbreaks can be triggered by various factors such as exposure to hot sun, cold wind, a cold or other illness, a weak immune system, or stress.
