MayoClinic.com describes cold sores, also called fever blisters, as small, fluid-filled blisters or superficial erosions that develop on or around the mouth, particularly on the border of the lip. Herpes simplex, the virus that causes cold sores, alternates between two cycles. During the lytic, or active, cycle, the virus is actively replicating and cold sores appear. During the latent cycle, the virus is inactive, held in check by the immune system.
Features
In a 2008 report in the "Archives of Internal Medicine," Dr. Christina M. Cernik describes a cold sore as a painful, 1 to 2-mm, fluid-filled blister that spontaneously ruptures, crusts and heals, over the course of 72 to 96 hours. However, says Cernik, cold sores sometimes develop in crops, especially during the first episode, so that a patient may exhibit several cold sores in various stages of healing.
Onset
In the 2008 edition of "Harrison's Principles of Internal Medicine," Lawrence Corey reports that patients typically develop cold sores between 1 and 26 days after acquiring the herpes simplex virus. Most patients report tingling, itching, burning or unusual sensitivity in the location where cold sores appear, up to three days before they appear. These symptoms signal that the virus has entered its lytic cycle.
Duration
According to Corey, an outbreak of cold sores can last anywhere from 3 days to 2 weeks. First-time outbreaks typically last longer than recurrent ones. In addition, people with immune system problems or those who take immune-suppressing drugs, such as prednisone, may also take longer to return to the latent cycle.
Location
Cernik states that 90 percent of cold sores develop on the border of the lip, called the vermillion. During the first outbreak, many patients develop lesions inside the mouth, especially on the palate, the gums, the lining of the cheeks and the back of the throat. About 5 percent of people, according to Cernik, develop cold sores elsewhere on the face, including the chin, cheeks and nose.
Recurrence
According to the American Social Health Association, 90 percent of the population becomes infected with the herpes simplex virus by the age of 50. Most suffer just one bout of cold sores. Twenty-five percent, however, experience recurrent episodes. Most people average 8 to 10 episodes during the first year, with fewer episodes each year thereafter. Common triggers for recurrence include menstrual periods, stress, physical trauma such as dental work and exposure to irritants such as wind or sun.
Treatment
Cernik says that doctors sometimes prescribe oral antiviral drugs, such as valacyclovir, especially during the first outbreak of cold sores when lesions tend to be more severe and numerous. Cernik notes that over-the-counter medications containing topical anesthetics can provide relief from pain and itching due to cold sores. However, unlike antiviral drugs, these medications have no effect on the cycle of cold sores.
References
- "Archives of Internal Medicine"; "The Treatment of Herpes Simplex Infections; C. Cernik et al.; 2008
- "Harrison's Principles of Internal Medicine, 23rd Edition"; A.S. Fauci et al.; 2008
- American Social Health Association: Oral Herpes
- Mayo Clinic: Cold Sores
