The evaluation of cold sores begins with a medical history and physical examination.

The diagnosis of cold sores can be made on physical examination.

Testing may be performed to confirm the diagnosis.

Tests that may be used to evaluate cold sores may include:

• A viral culture
• Tzanck smear
• A special stain is added to a tissue specimen on a slide can confirm herpes infection in questionable cases.
• Serum antibody titers can detect herpes simplex