Table of Contents
Disorders caused by viruses
Hairy leukoplakia is a white, corrugated or “hairy” “coating” on the lateral borders of the tongue. It is one of the relatively few conditions seen in the oral cavity which is associated almost exclusively with AIDS. Unlike Thrush, it is not easily scraped off. It is painless, but patients occasionally complain of its appearance and texture. It is caused by the body’s reaction to the Epstein-Barr virus (responsible for Mononucleosis), and can be eliminated with a viral antibiotic like acyclovir (Zovirax®), famciclovir (Famvir®) or valacyclovir (Valtrex®).
This condition is rarely seen in patients not infected with HIV. However, some healthy patients may develop a “callous” on the lateral borders of the tongue due to the nervous habit of continually scraping the tongue over the teeth. This can lead to embarrassment if the dentist suggests an AIDS test to a person who believes such a suggestion is an insult! It is never meant as a value judgment. Hairy Leukoplakia is not contagious.
Herpes Zoster (better known as shingles) is caused by the same virus that causes Chicken Pox. Herpes zoster “hides out” in a somatic nerve branch after the initial Chicken Pox infection (which usually happens in childhood), and flares up again later in life when the immune system begins to fail. Shingles is common in otherwise healthy elderly persons. It generally does not occur in younger people unless they are concurrently infected with the AIDS virus. The distribution of the rash on the body is the key to the diagnosis of shingles, and distinguishes the herpes zoster virus from other forms of herpes viruses. The distribution of the rash caused by herpes zoster in shingles is almost always on one side of the body, and is confined to the distribution of a single nerve root. The skin surface distribution of each spinal or cranial nerve is called a dermatome. The image above shows a rash which is confined to the dermatome defined by the third branch of the trigeminal nerve. It is outlined in blue to make it easier to see. Click the image to see larger images, as well as a great deal more on the concept of somatic dermatomes. Shingles infections are quite painful, and they generally go away after four or five weeks, but shingles may reoccur again at a later date. It frequently leaves those so afflicted with “postherpetic neuralgia” (PHN), which is severely sensitive skin, well after the infection.
The images below shows the distribution of the herpes zoster rash from the frontal aspect, and what it might look like on the hard palate of the mouth. Note the sharp delineation between the affected side and the unaffected side in in both images, These images are presented compliments of Dr. Jonathan D. Trobe, MD at the University of Michigan.
In the mouth, it looks very much like a typical intraoral herpes simplex infection. It is, again, identified by its distribution. It is limited to one side of the affected organ. The image above and on the right shows the Herpes zoster virus infecting half of the upper hard palate. It is easy to confuse Herpes zoster with Herpes simplex which may occur in the same distribution purely by chance.
While the Herpes Zoster virus is contagious, Shingles, surprisingly is not. Since a large percentage of the population already has been exposed to Chicken pox, most people harbor an immunity, and the probability that anyone will develop this disease depends more on the state of their immune system than on recent exposure to the virus.
The Herpes simplex virus (HSV) is the most commonly occurring virus in the oral cavity. There are two distinct subcategories of HSV; HSV-I is primarily associated with infections in and around the mouth, and HSV-II is primarily associated with genital lesions. However, recent studies have shown that this type of site predilection is changing, probably due to changing sexual habits. current estimates show that approximately 11% of genital herpes infections are caused by HSV-I and about 2.5% of primary Herpes stomatitis infections (mostly in immunocompromised adults) are caused by HSV-II.
Herpes Simplex (type I) is the virus that causes cold sores (herpes labialis) in normal, healthy adults. The image above shows a recurrent herpetic infection, in other words, a typical cold sore, sometimes called a fever blister due to its propensity to appear when the patient has a cold or other febrile (fever causing) illness. This is another bug that, like Shingles, tends to “hang out” in a nerve root for the life of the patient after the initial infection, which often occurs in childhood. Once infected, the patient remains infected for life. The virus remains dormant inside the nerve root most of the time until the patient suffers an illness or other problem which lowers his immune response. The virus takes advantage of the drop in immune response to flare up in the typical cold sore seen in this image. The soreness on the lip may be treated in a number of ways, however the systemic symptoms of fever, malaise and muscular soreness are more persistent and are more quickly alleviated with acetaminophen and antiviral antibiotics. Click the image above for more information on recurrent herpes labialis, its treatment modalities, and many more images of herpes infections.
The image above is what the initial infection may look like when a child, or young adult is firstinfected with the Herpes Simplex virus. While most young children and adolescents experience a subclinical infection (no outward signs of the infection), a small percentage will develop “Primary Herpes stomatitis“. As you can see, it can look quite severe with blisters both inside and outside the mouth. (“Stomatitis” means inflammation of the entire mouth.) It starts out with “prodromal” symptoms including fever, malaise, headache and irritability, and then progresses after several days into severe gingival (gums) inflammation followed by the outbreak of numerous small blisters both inside and around the mouth. The blisters break leaving behind very painful sores with yellowish centers and red borders. The sores in the mouth are generally accompanied by severe pain, foul odor and increased salivation. Often the sores extend into the throat (pharyngitis). On rare occasions, the primary herpes infection can be confined to the throat. In any case, the patient is quite sick, but this primary infection will disappear after 10-14 days with rest, Tylenol®l and lots of fluids. In healthy people, this infection happens only once in a lifetime. Later in life, the presence of the virus only becomes apparent whenever an “ordinary” cold sore appears.
Approximately 30% – 40% of patients who have been exposed to HSV will develop recurrent infections that will manifest as either recurrent herpes labialis (cold sores on the lips) or recurrent intraoral herpes. The sores are generally triggered by exposure to sunlight, fatigue, stress, hormonal changes such as menstruation, gastrointestinal disturbances and oral trauma.
Whenever an adult appears in a clinic with a case of Primary Herpes Stomatitis, this infers a severely depressed immune response, and the dentist might consider referring the patient to a physician for diagnosis of an underlying disorder. Adults presenting with severe herpes stomatitis should consider being tested for HIV. It must be remembered, however, that a primary herpes stomatitis can happen at any time of life if the patient has never before had a cold sore. Click on the image to see larger views of this condition.
The presence of this type of infection in the mouth does not indicate the presence of HIV, although it is more common in AIDS patients than in the non-HIV population. This can happen to anyone who harbors the Herpes Simplex virus. Left alone, provided the patient is not immunologically compromised, it disappears in 10 to 14 days. The herpes simplex virus is very contagious and if one person in a family develops a cold sore, then others in the family may develop one as well. Herpes simplex blisters can sometimes occur in the oral cavity on tissues not generally associated with cold sores. They always happen on tissue that is firmly bound down to underlying bone, such as the gums immediately around the teeth or on the roof of the mouth. As you can see, the appearance of this infection in the mouth can easily be confused with Herpes Zoster (shingles), especially if it occurs on only one side of the mouth. The viruses are closely related, and the blisters in the oral cavity can look identical.
Treatment or herpes infections
The treatment of herpes stomatitis is essentially palliative (treating the symptoms only). In healthy individuals, bedrest, high fluid intake and Tylenol work best to alleviate the symptoms. Aspirin and nonsteroidal anti-inflammatories like Motrin® and Alive® are best avoided in viral infections.
New antibiotics like acyclovir (Zovirax®), famciclovir (Famvir®) or valacyclovir (Valtrex®) are effective in suppressing the Herpes virus and will generally alleviate the symptoms within a fairly short time. Systemic drugs like these are generally used in very severe cases in immunocompromised patients, or in herpes infections of the eye. In patients exposed to a lot of sun who are prone to outbreaks of recurrent herpes labialis, a prophylactic regimen of 400 mg of acyclovir twice a day may prevent the outbreaks Unfortunately, the antibiotics do not often “cure” the disease since the virus continues to remain in an inactive form inside a nerve root waiting for another chance to cause an outbreak.
Recently, the Food and Drug Administration has approved penciclovir 1% topical cream for the treatment of herpes labialis. This is applied every two hours while awake, and will help to shorten the duration and severity of the cold sore. Acyclovir cream (Zovirax®) works, but is less effective than penciclovir.
Lysine (available at most drug stores) has been reported to reduce the severity of recurrent outbreaks if taken in high enough doses (2-3 gm) at the first prodromal signs (burning, tingling
For more information on HSV-II (genital herpes), please see my section on Oral Cancer
Warts are caused by a virus. In the oral cavity, they tend to be somewhat flatter than the type occurring on hands, but if they are dried with air, the tiny projections characteristic of regular warts become evident. The causative agent is the Human Papillomavirus (HPV). These growths generally are not painful. They may be removed using lasers, cautery or cold steel blades. A majority of these lesions have no consequences beyond the primary papilloma. Some, especially toward the back of the mouth or throat may have more serious consequences discussed below. HPV is contagious.
There are about 200 different strains of HPV. Most strains are relatively harmless, or may cause papillomas like the one in the image above. Some strains of HPV cause genital warts and are now known as the cause of cervical cancer (cancer of the uterus) as well as anal, vulvar and penile cancers. Although there are eighteen strains with serious pathological consequences, one strain in particular, HPV-16 is quite dangerous in the oral cavity. It is a major causative agent in oral cancers, and is transmitted to the oral cavity via vigorous oral/sexual contact (oral sex). As a result of the stark increase in promiscuous sexual activity since the late 1960’s, this strain of HPV is increasingly problematic, and seems to account for the serious rise in the incidence of oral cancers in younger people, many of whom do not smoke or drink regularly. For much more on this subject, please see my page on Oral Cancer.
Five strains of HPV cause oral papillomas. These include 6, 7 11, 16 and 32. Note that young persons who contract oral papillomas, even those infected with HPV-16, will probably clear the infection eventually if their immune systems are not adversely affected by other chronic diseases or lifestyle issues like drug or alcohol addictions.
Because HPV-16 is associated with vigorous sexual oral/genital contact (oral sex), most of the “warts” associated with this strain would most likely occur in the back of the oral cavity, toward the back of the throat, around the tonsils, on the soft palate, at the base and sides of the tongue, etc. They will rarely be found toward the front of the mouth like the one pictured above. HPV-16 is NOT transferred by “ordinary” kissing, but may be transmitted by vigorous open mouth deep (French) kissing.
There is a saliva test that a dentist can perform that can diagnose hidden cases of HPV. Dentists interested in offering this service to their patients can visit the website of OralDNA Labs to learn about this simple and accurate process.
In general, HPV is implicated as a causative agent only in squamous cell carcinomas occurring at the base of the tongue (i.e. the non movable area in the throat) the pharyngeal tonsils and the upper throat. It is in this subset of oral squamous cell cancers that we find the stark increase in oral cancers in young adults who neither drink nor smoke. An association between HPV 16 and squamous cell carcinomas of the anterior tongue and other more anterior oral tissues has not yet been demonstrated.
Herpes Simplex type I (HSV-1) prefers to infect the face and oral cavity. It is the virus most responsible for traditional cold sores and primary herpes stomatitis. There is, however a second variety of Herpes that prefers to infect the genital areas. Herpes Simplex Type II (HSV-2) is called “genital Herpes” because of its venereal (sexually transmitted) qualities. Both varieties produce similar lesions, the difference between them being their site specific preferences. Both establish latency (take up permanent residence) in nerve roots and once established, tend to cause occasional outbreaks with active lesions (sores) in areas of the body serviced by that particular nerve root. HSV-1 prefers to live in the trigeminal nerve root where it causes lesions in the oral cavity and on the face. HSV-2 takes up residence in the sacral ganglion at the base of the spine where it may cause genital lesions (see the dermatome chart on the Herpes zoster page).
Even though each type has site specific preferences, the viruses are genetically similar and can take up residence in nerve roots in other parts of the body, including in each other’s territory. Outside of their own home territories, however, neither virus is especially virulent, and rarely cause recurrent outbreaks.
HSV-2 causes approximately 90% of all cases of genital herpes. Genital herpes caused by HSV-1 is generally much milder than that caused by HSV-2. HSV-1 is usually transferred to the genital area by direct oral/genital contact, although the virus is present in the saliva of infected individuals. Thus the use of saliva as a lubricant can, in fact, transfer HSV-1 to the genital area. HSV-1 is found in only about 10% of all cases of genital herpes, however most people infected with HSV-1 in the genital area have few, if any, outbreaks after the initial episode. HSV-2 prefers to live in this area and causes a much more virulent infection there.
On the other hand, HSV-1 causes almost all cases of oral and facial herpes. Oral herpes caused by HSV-2 almost never reoccurs, except in immunocompromised patients.