1. Adult Skin Problems Slideshow Pictures
2. Take the Skin Conditions Quiz
3. Gallery of Skin Problems Pictures

Medical Author:

Mohamad El Mortada, MD

Medical Author:

MaryAnn Tran, MD

Medical Author:

Corrine Young, PharmD

Medical Author:

Mary D. Nettleman, MD, MS, MACP

Mary D. Nettleman, MD, MS, MACP

Mary D. Nettleman, MD, MS, MACP is the Chair of the Department of Medicine at Michigan State University. She is a graduate of Vanderbilt Medical School, and completed her residency in Internal Medicine and a fellowship in Infectious Diseases at Indiana University.

View Full Profile

Medical Editor:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

View Full Profile

In this Article

• Herpes simplex infections (nongenital cold sores) facts
• What are herpes simplex infections?
• What causes cold sores?
• What makes herpes (cold sores) recur?
• How do cold sores spread?
• What are the signs and symptoms of cold sores?
• What is primary oral herpes?
• What does recurrent herpes look like?
• How long do cold sores last?
• What are the possible complications of oral herpes (cold sores)?
• What other conditions can look like oral herpes (cold sores)?
• What is angular stomatitis?
• What are canker sores?
• How is oral herpes diagnosed?
• What is the treatment for cold sores, are there any home remedies, and what medications are used?
• Patient Comments: Herpes Simplex Infections (Cold Sores) - Treatments
• Patient Comments: Herpes Simplex Infections (Cold Sores) - Describe Your Experience
• Patient Comments: Herpes Simplex Infections (Cold Sores) - Treatments
• Herpes Simplex Infections (Non-Genital) Index

After infection, the virus enters the nerve cells and travels up the nerve until it comes to a place called a ganglion. There, it lays quietly in a stage that is referred to as "dormant" or "latent." At times, the virus can become active and start replicating again and travel down the nerve to the skin, causing sores and blisters. The exact mechanism behind this is not clear, but it is known that some conditions seem to be associated with recurrences, including

• a fever, a cold, or the flu;



• ultraviolet radiation (exposure to the sun);



• stress;



• changes in the immune system;



• trauma to the involved area;



• sometimes there is no apparent cause of the recurrence.

Infections caused by HSV are contagious. The virus is spread from person to person by kissing, by close contact with herpetic lesions, or even from contact with apparently normal skin that is shedding the virus. Infected saliva is a common means of virus transmission. People are most contagious when they have active blister-like sores. Once the blisters have dried and crusted over (within a few days), the risk of contagion is significantly lessened. However, a person infected with HSV can pass it on to another person regardless of the presence or absence of symptoms and visible sores or blisters. This is because the virus is sometimes shed in saliva even when sores are not present. Despite popular myth, it is almost impossible to catch herpes (cold sores) from surfaces, towels, or washcloths.

Picture of cold sores on the lips (fever blisters, HSV-1, or herpes simplex infection type 1)