Section 8. Mouth and Dental Disorders

Chapter 112. Mouth Sores

Topics: Introduction | Canker Sores | Oral Herpes Simplex | Other Mouth Sores

Oral Herpes Simplex

Infection of the mouth with herpes simplex virus causes recurring sores (often called cold sores), in which small fluid-filled sores develop on the skin, lips, or mouth in single or multiple clusters.

The first eruption of sores due to infection with oral herpes simplex virus is called primary herpes. It is usually contracted in childhood. Primary herpes may be mild or severe, but it often affects large areas of the mouth and always the gums. Any subsequent eruption of the sores is called secondary herpes. Secondary herpes is a reactivation of the virus rather than a new infection. There are at least two forms of herpes simplex virus. In the past, herpes simplex virus type 1 only caused sores above the waist, and type 2 only below the waist (genital herpes (see Section 17, Chapter 198)). Now, however, either type can cause sores anywhere on the body. Herpes simplex virus type 2 tends to be more severe than type 1.

Typically, a previously uninfected child acquires the virus from contact with an adult who has a cold sore. In rare cases, a person first acquires herpes simplex virus in adulthood, also after contact with someone with a cold sore.

A person is capable of spreading the infection (contagious) from the time the tingling sensation that precedes the development of a sore (the prodrome) is experienced to the time at which the sore has completely crusted over. It is unknown whether herpes can be spread by sharing a glass or touching something that an infected person has touched.

Symptoms

When primary herpes is acquired in childhood, the infection causes gum inflammation and extensive mouth soreness. Fever, swollen lymph nodes in the neck, and general discomfort may develop. A child may be cranky and cry continually. However, many cases are mild and go unrecognized. Parents often mistake the problem for teething or another illness. In more severe cases, small blisters form in the child's mouth. These blisters may not be noticed because they rupture within a day or two, leaving many ulcers. The ulcers may occur anywhere in the mouth but always include the gums. Though the child gets better in a week to 10 days, the herpes simplex virus never leaves the body.

When primary herpes is acquired in adulthood, symptoms are usually more severe and include multiple rapidly developing painful sores on the gums and other parts of the mouth.

Unlike primary herpes, which causes widespread mouth soreness, the flare-ups of secondary herpes usually produce a single raw, weeping open sore on the outer lip that later crusts over before healing within 2 or 3 weeks. The sore is sometimes called a cold sore or fever blister. Less commonly, a cluster of blisters (vesicles) forms on the roof of the mouth. These small blisters run together and quickly break down into a sore. There is no crusting stage.

Flare-ups are commonly triggered by sunburn on the lips, certain foods, anxiety, a cold (hence the name "cold sore"), fever, or anything that lowers the body's resistance to infection. Certain dental procedures can cause a flare-up as well; if a cold sore already exists, dental visits should be postponed until the sore heals.

Although merely a painful annoyance for most people, flare-ups of oral herpes simplex infection can be life-threatening for a person with an impaired immune system. Impairment of the immune system can be caused by diseases (such as AIDS), chemotherapy, radiation therapy, or a bone marrow transplant. In such people, large, persistent sores in the mouth can interfere with eating; spread of the virus to the brain can be fatal.

Treatment

Treatment for primary herpes aims to relieve the pain so that the person can sleep, eat, and drink comfortably. Pain may keep a child from eating and drinking, which, combined with a fever, can quickly lead to dehydration. Thus, a child should drink as much fluids as possible. An adult or older child can use a prescribed anesthetic mouth rinse such as lidocaine to reduce pain. A mouth rinse containing baking soda may also be soothing.

Treatment for secondary herpes works best when started before the sore erupts--as soon as the person has the sensation (the prodrome) that an attack is starting. Taking vitamin C (1,000 to 2,000 milligrams per day) during the prodrome may make the attack less severe. A doctor may prescribe penciclovir cream or amlexanox paste, which is applied during the prodrome to shorten the duration and severity of the outbreak. The virus itself cannot be permanently eliminated.

Protecting the lips from direct sunlight by wearing a wide-brimmed hat or by using lip balm containing sunscreen can reduce the possibility of a flare-up. Also, a person should avoid activities and foods that are known to cause flare-ups. Anyone who suffers frequent, severe flare-ups may try taking lysine (available at health food stores) indefinitely. Levamisole, available by prescription, is another drug that seems to reduce recurrences.

For people with severe herpes simplex and for people with an impaired immune system, acyclovir or penciclovir capsules may be prescribed to prevent or limit the severity of the infection. Corticosteroids are not used for herpes simplex because they may allow the infection to spread.