Cold sores are small blisters that develop on the lips or around the mouth and are caused by the herpes simplex virus (HSV) . The most common strain of the virus causing cold sores is HSV-1, but in rare cases, cold sores can also be caused by HSV-2. Both types of the virus can also cause sores on the genitals and can be spread by oral sex. 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, towels, or razors. The virus can spread even if you dont see the sores, and many people who are infected with the virus 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. A return of cold sores may be triggered by viral infection or fever, hormonal changes, stress, fatigue, being in the sun or wind, or other factors. Cold sores usually clear up without treatment within 7 to 10 days, but prescription antiviral medicine or creams can help sores heal more quickly. If you have frequent recurrent infections, you may develop cold sores in the same place every time, and they may grow in size and cause irritation and pain.
To prevent getting cold sores, you can avoid kissing people with them or sharing objects with them. If you have a cold sore, you should avoid close contact with others, wash your hands frequently, and avoid touching the sore.