health

The cause of cold sores is usually herpes simplex virus 1 or HSV-1,
although occasionally type 2 may cause the process. The virus enters the
body through tiny breaks in the tissues lining the mouth, which is one
reason it can easily be spread by kissing or by sharing drinking glasses and
other food utensils. HSV-1 then lies dormant in the cells of the nervous
system until it is activated by stress, an upper respiratory infection, or
some other trigger. It then travels back down the nerves to the skin surface,
usually in the same area of skin each time. HSV-2 oral infection
usually does not have recurrences.

The symptoms of cold sores have already been described. In most
cases, people do not need to see the doctor for ordinary cold sores. They
should, however, make an appointment if they have any of the following
symptoms or conditions:

• They have HIV or any other illness that weakens the immune
  system.
  
• The cold sores do not heal on their own by the end of two weeks.
  
• The patient’s eyes feel sore or irritated.
  
• The cold sores recur frequently.
  
• The blisters are unusually large or painful.