Canker SoresPage 1 of 3
Fever Blisters and Canker
Fever blisters and
canker sores are two of the
most common disorders of the mouth, causing discomfort and annoyance to
millions of Americans. Both cause small sores to develop in or around the
mouth, and often are confused with each other. Canker sores, however, occur
only inside the mouth--on the tongue and the inside linings of the
cheeks, lips and throat. Fever blisters, also called cold sores, usually occur
outside the mouth--on the lips, chin, cheeks or in the nostrils. When
fever blisters do occur inside the mouth, it is usually on the gums or the roof
of the mouth. Inside the mouth, fever blisters are smaller than canker sores,
heal more quickly, and often begin as a blister.
Both canker sores and fever blisters have
plagued mankind for thousands of years. Scientists at the National Institute of Dental and
Craniofacial Research, one of the federal government's
National Institutes of Health, are seeking ways to better control and ultimately prevent these and other oral
Canker Sore and Fever Blister Medication
In ancient Rome, an epidemic of fever
blisters prompted Emperor Tiberius to ban kissing in public ceremonies. Today
fever blisters still occur in epidemic proportions. About 100 million episodes
of recurrent fever blisters occur yearly in the United States alone. An
estimated 45 to 80 percent of adults and children in this country have had at
least one bout with the blisters.
What causes fever
are caused by a contagious
virus called herpes simplex. There are two types of herpes simplex virus. Type 1
usually causes oral herpes, or fever blisters. Type 2 usually causes genital
herpes. Although both type 1 and type 2 viruses can infect oral tissues, more
than 95 percent of recurrent fever blister outbreaks are caused by the type 1
Herpes simplex virus is highly contagious when
fever blisters are present, and the virus frequently is spread by kissing.
Children often become infected by contact with parents, siblings or other close
relatives who have fever blisters.
A child can spread the virus by rubbing his or her
cold sore and then touching other children. About 10 percent of oral herpes
infections in adults result from oral-genital sex with a person who has
active genital herpes (type 2). These infections, however, usually do
not result in repeat bouts of fever blisters.
Most people infected with the type 1 herpes simplex
virus became infected before they were 10 years old. The virus usually
invades the moist membrane cells of the lips, throat or mouth. In most
people, the initial infection causes no symptoms. About 15 percent of
patients, however, develop many fluid-filled blisters inside and outside
the mouth 3 to 5 days after they are infected with the virus. These may
be accompanied by fever, swollen neck glands and general aches. The blisters
tend to merge and then collapse. Often a yellowish crust forms over the
sores, which usually heal without scarring within 2 weeks.
The herpes virus, however, stays in the body.
Once a person is infected with oral herpes, the virus remains in a nerve
located near the cheekbone. It may stay permanently inactive in this site, or
it may occasionally travel down the nerve to the skin surface, causing a
recurrence of fever blisters. Recurring blisters usually erupt at the outside
edge of the lip or the edge of the nostril, but can also occur on the chin,
cheeks, or inside the mouth.
The symptoms of recurrent fever blister
attacks usually are less severe than those experienced by some people after an
initial infection. Recurrences appear to be less frequent after age 35. Many
people who have recurring fever blisters feel itching, tingling or burning in
the lip 1 to 3 days before the blister appears.
What causes a recurrence of
Several factors weaken the body's defenses and
trigger an outbreak of herpes. These include emotional stress, fever, illness,
injury and exposure to sunlight. Many women have recurrences only during
menstruation. One study indicates that susceptibility to herpes recurrences is
inherited. Research is under way to discover exactly how the triggering factors
interact with the immune system and the virus to prompt a recurrence of fever
What are the treatments for