Exams and Tests

Your doctor can diagnose cold sores by asking questions to find out whether you've been exposed to the herpes simplex virus (HSV) and by examining you. No further testing is usually needed.

There are two types of herpes simplex virus: HSV-1 and HSV-2. Both virus types can cause lip and mouth sores (herpes labialis) and genital herpes if your skin comes into contact with either type.

If it is not clear that you have cold sores, herpes tests may be done. The doctor takes a sample of fluid from a sore and has it tested. Having the sample taken is usually not uncomfortable even if the sore is tender or painful.

Treatment Overview

There is no cure for cold sores, nor is there a cure for the herpes simplex virus (HSV) that causes them. Most cold sores will go away on their own. But medicines may slightly reduce the duration of cold sores and sometimes prevent a future outbreak.

Treatment with medicines depends on whether you are having a first outbreak or a recurrent outbreak or are trying to prevent future outbreaks.

When treating a first outbreak of cold sores, oral antiviral medicines may reduce pain and slightly improve healing time.

For treatment of recurrent cold sores, the following medicines may reduce the severity and duration of the outbreak:¹

• Topical creams or ointments, which are available with or without a prescription, can reduce pain, itching, and healing time.
• Oral antiviral medicines, which are available by prescription only, may be used when the first symptoms (such as burning or itching) begin. These medicines have little effect after the sore develops.

Oral antivirals may also be taken daily to prevent recurring cold sores, especially in people who have frequent and painful outbreaks.

If you have a weakened immune system and develop cold sores, you may need higher doses of these medicines to control your symptoms or daily doses to prevent outbreaks.

Although it is rare, children and adults with weakened immune systems may also need to take antibiotics during severe episodes of cold sores to treat bacterial infections that may develop.

Other treatments

The first episode of cold sores can be so painful that you may have trouble eating, drinking, and sleeping. A child who has a fever and many mouth sores may need to be encouraged to drink water and other fluids to prevent dehydration.

Adults and older children who have a painful first episode of cold sores may sometimes need a prescription-strength medicated mouth rinse to reduce pain.

Complementary medicine

Several complementary medicine treatments are available if you wish to try an alternative way to ease your symptoms.

Vitamin C, lysine supplements, and lemon balm are examples of complementary treatments that may provide some relief during a cold sore outbreak. Vitamin C may be taken as an oral tablet, in a cream that can be put on the cold sore (topical cream), or as liquid vitamin C applied to the cold sore. Lysine supplements are taken as pills, and lemon balm is available in a topical cream.

Zinc oxide topical cream may reduce the duration of an outbreak.¹