Cold sores are a common skin condition that affects up to 45 percent of the adult population, according to Brown University Health Services. The sores can be painful and unsightly, as well as highly contagious. Although there's no cure, there are treatments that can help with symptoms and steps you can take to keep cold sores from recurring.
Identification
Although some people use the terms "cold sore" and "canker sore" to mean the same thing, they're different conditions. Canker sores are bacterial infections inside the mouth, whereas cold sores are on the outside of your mouth and are caused by the Type 1 herpes simplex virus, or HSV-1. The virus hides in nerve cells after you're infected, making it impossible for antibodies to kill it, and simply stays dormant until something causes it to flare up. Although most people get infected when exposed to the virus, only 10 percent will actually develop sores.
Symptoms
During your initial infection with HSV-1, you may have a sore mouth, difficulty eating, swollen glands, fever and fatigue. If you develop a cold sore, it will appear two to 20 days after exposure to the virus and will typically be a fluid-filled red blister that lasts from seven to 12 days, progressing through five stages: tingling, called the prodrome stage; blistering; weeping, also called the ulcer stage, in which the blisters break open and ooze liquid; scabbing, in which the sore attempts to scab over but may break open, bleed, itch and burn until a newer scab is formed; and finally, the healing phase. About six percent of people will have another sore within one week and 13 percent within two weeks, according to the Brown University Health Center.
Causes
HSV-1 is the cause of cold sores, not to be confused with herpes simplex virus type 2, responsible for genital herpes. HSV-1 is transmitted from a person who has an active lesion via shared eating utensils, razors or towels, as well as kissing. Oral-genital contact can also spread the virus. Most people get Type 1 infections during infancy or childhood from close contact with an infected family member or friend.
Significance
According to the Mayo Clinic, herpes simplex infection of the eye causes scarring of the cornea and is a leading cause of blindness in the United States. About 1,500 to 2,200 babies under 1 month old contract herpes each year in the United States, as reported by the American Academy of Family Physicians, and if left untreated, is fatal in up to 85 percent of cases. The majority of infant herpes simplex infections are caused by HSV-2, but about 30 percent are caused by HSV-1. The virus behind cold sores was also determined to be a major cause of the protein plaques found in the brains of Alzheimer's patients in a study led by Professor Ruth Itzhaki at Manchester University's Faculty of Life Sciences in 2008. The team discovered 90 percent of plaques in the brains of Alzheimer's sufferers contain HSV-1 DNA.
Prevention
To prevent the spread of HSV-1, avoid sharing cups, utensils, food, towels or even lip balms while you have an active cold sore, according to the Mayo Clinic. You should also avoid kissing and any other skin contact with the sore and wash your hands carefully before touching another person. To avoid a cold sore outbreak if you're already infected with the virus, try to avoid conditions that stress your body, like getting a cold or the flu, lack of sleep or staying in the sun for long periods of time without applying sunblock to your lips and face. Dr. Andrew Weil suggests preventing recurrences by avoiding foods rich in the amino acid arginine, such as chocolate, cola, beer, grain cereals, chicken soup, gelatin, seeds, nuts and peas, which can activate the virus. You should also get a new toothbrush after an outbreak, since the virus can live in your toothbrush and reinfect you.
Treatment
The best time to treat the symptoms of an active cold sore is during the tingling prodrome stage, although it can be treated at any time with topical medications such as lidocaine or benzocaine or oral medicines like acyclovir, famciclovir or valacyclovir. You can also take an over-the-counter pain reliever and apply ice or warm compresses to the blisters to ease the pain. You should never squeeze, pinch or pick at any blister.
