Fever blisters---also known as cold sores---are a symptom of infection with one or both types of the herpes simplex virus. The American Social Health Association reports that such infections are far from uncommon. In fact, 90 percent of Americans carry the virus by the age of 50. Not all infections are symptomatic, however. Some people never experience fever blisters while others average six or more outbreaks per year.
Onset
Dr. Lawrence Corey states in "Harrison's Principles of Internal Medicine" that fever blisters develop between one and 26 days after exposure to the virus. The average interval is seven days.
Duration
First outbreak fever blisters last longer than recurrent ones. The American Social Health Association explains that first outbreak lesions may last up to 20 days, compared to about seven days for recurrent ones. In almost all cases, fever blisters heal without scarring.
Location
According to a 2008 report in the "Archives of Internal Medicine," 90 percent of lesions occur on the border between the lip and the surrounding facial skin. The remaining 10 percent of lesions occur elsewhere on the face, particularly on the chin and the area between the nose and the lips. During the first outbreak, fever blisters tend to be mulitiple---often to the point that they become confluent--and occur on both sides of the body. Subsequent outbreaks are characterized by fewer lesions, usually on just one side of the body.
Related Symptoms
Many people with fever blisters experience tingling, itching, burning, soreness or hypersensitivity at the sites where lesions later appear for between two hours and two days before diminishing. Some patients also report flu-like symptoms such as fever, fatigue, headache, sore muscles and poor appetite that accompanying the lesions; these symptoms subside as the lesions start to heal. In most cases, flu-like symptoms are most severe for the first outbreak and become less severe with recurrences.
Diagnosis
Cold sores can almost always be diagnosed clinically, which means on the basis of the patient's history and physical findings. In complicated cases, a physician or dentist may order laboratory tests on a sample of the patient's blood or a swab or scraping from the lesion.
Treatment
The American Dental Association notes that most fever blisters resolve without treatment. If the lesions prove particularly troublesome, however, a health care provider may prescribe oral or topical antiviral medications which decrease the duration and severity of the outbreak. The U.S. Food and Drug Administration also has approved one over-the-counter remedy, topical Abreva, as a treatment for fever blisters.
Prevention
The American Academy of Dermatology cautions that the virus can be transmitted by kissing or sharing objects such as eating utensils or towels. The virus is often spread by people who themselves show no symptoms--a process known as asymptomatic shedding. People who do show symptoms should refrain from activities that promote the spread of the virus such as kissing, oral sex and sharing objects that come into contact with the mouth.
References
- American Social Health Association: Learn About Herpes: Oral Herpes
- "Harrison's Principles of Internal Medicine, Seventh Edition"; A.S. Fauci, E. Braunwald, D.L. Kasper, S.L. Hauser, D.L. Longer, J.L. Jameson and J. Loscalzo; 2008
- "Archives of Internal Medicine;" The Treatment of Herpes Simplex: An Evidence-Based Review; C. Cernik, K. Gallina, and R.T. Brodell; June 2008
- American Academy of Dermatology: Herpes Simplex
- American Dental Association: Canker Sores, Cold Sores, and Common Mouth Sores
