Primary Herpes Simplex (HSV) Infection
Primary Herpes Simplex (HSV-I) type 1 produces the most common viral infection
in the oral cavity. It most often occurs in children under 6 years of age
but can involve older patients. In most children primary infection is sub-clinical
(without clinical signs or symptoms); about 13% of children have had symptomatic
herpes by age 9.
The herpes simplex viruses are virtually ubiquitous in the
general population; over 90% of adults have antibodies to herpes simplex virus
by the fourth decade of life. Once an individual is infected, the virus spreads
to regional mass of nerve tissue, ganglia (e.g., the trigeminal ganglion),
where it remains latent but can be reactivated whenever conditions are
The causes and the
course of the disease
Both herpes simplex types 1 and 2 may cause both orofacial
and genital infections, but HSV-I is more frequently responsible for lesions in
and about the mouth ranging from the relatively trivial cold sore to a
vesiculoinflammatory (having small blisterlike elevations on the skin with
fluid in them) eruption. These lesions typically
involves large areas of the oral mucosa, the moist surface tissues that line
the mouth, throat and lips. This
condition is called gingivostomatitis.
In addition, herpes simplex virus infection may involve the
membranes of the eye, causing the keratoconjunctivitis. In newborn infants or
immuno-compromised (with depressed immune system) adults, the infection may
involve visceral organs (e.g., lungs, liver) or produce encephalitis
(inflammation of the brain) or fatal disseminated disease.
Recurrent herpetic infections develop in about one third of those patients
who have had a primary infection. Herpes labialis is the most frequent
type of recurrent infection. It usually is seen as a cluster of vesicles
appearing around the lips after a systemic illness or other stress-fill
situation. Ultraviolet light and mechanical stimuli may also produce recurrences.
The clinical features
The "cold sore" or "fever blister" as is well known
to all, constitutes a vesicular lesion usually located around mucosal orifices
such as the lips and noses. Often several lesions appear simultaneously
or in quick succession. There is frequently a history of previous respiratory
infection or fever, exposure to sunlight or cold, or trauma to the area,
but whether these influences in fact activate the virus remains unclear.
The vesicular lesion begins with a focus of intracellular
and intercellular edema followed by ballooning degeneration of epidermal cells
and acantholysis (separation of cells) with the formation of an intraepithelial
vesicle (blister). Individual epidermal cells in the margins of the vesicle or
lying free within the fluid develop intranuclear inclusions composed of live
and dead virions. Sometimes several cells fuse to produce polykaryons or giant
cells that can be identified in smears of blister fluid (Tzanck preparations).
The vesicles are prone to burst to produce superficial ulcerations, and in most
cases, in the course of a few days are covered with a fibrinous coagulum and
Primary herpetic gingivostomatitis is a more florid form of herpetic infection
of the oral cavity that occurs in the compromised host (debilitation, impaired
immunity, immunosuppressive therapy, and in the very young who lack antibodies).
The lips and gingival and buccal mucosa are involved but sometimes also
the tongue and retropharynx. The individual lesions may begin as vesicles
but may extend into the mucosa and deep cutaneous layers, favoring systemic
dissemination. Coalescence of the lesions leads to denudation of large
areas of the mucosa. There is a commensurate greater inflammatory reaction
and consequent edema and erythema.
The primary episode of herpetic gingivostomatitis is
characterized by constitutional symptoms such as malaise, fever and regional
lymphadenopathy. Acute ulcerative gingivostomatitis occurs as a result of virus
replication in the affected tissues. Vesicular eruptions may occur throughout
the mouth. The gingivae are red and swollen and bleed readily. They may have a
mottled appearance in the maxillary areas. Touching them or attempting to
consume food causes severe pain.
Herpetic infection of the digits occurs through a break in the skin and
results from localized virus replication which causes swelling, redness,
and tenderness with subsequent vesiculation. Healing follows in 2 weeks;
as in other HSV infections, latency and periodic reactivations are common.
The differential diagnosis
There are two types of herpes simplex virus that cause
disease in humans. The type 1 virus is primarily associated with infections of
the skin and oral mucous membrane, and type 2 with infections of the genitalia
(although the converse can and does occur).
The diagnosis of primary herpetic gingivostomatitis is
usually made on a clinical basis. The patient has a number of vesicles or small
painful ulcers throughout the oral cavity. A history of systemic signs and symptoms
of a viral illness helps to establish the diagnosis. The differential diagnosis
of primary herpetic gingivostomatitis has been reviewed in the differential
diagnosis of recurrent aphthous stomatitis. In addition, hand-foot-mouth
disease (viral etiology) needs to be considered because multiple pinpoint oral
vesicles and ulcers, as well as fever, are common signs. The absence of lesions
on the palms and soles eliminates hand-foot-mouth disease from consideration.
Herpangina (coxsackievirus) can generally he identified by the limited
distribution of the small vesicles and ulcers to the soft palate and
Confirmation of the viral infection by lahoratory methods is
available but not routinely used. The virus may be isolated in tissue culture
if fluid can be obtained from an intact vesicle. Primary infections are
associated with an increase in antibody titer, and paired acute and
convalescent sera may be studied.
There is no specific treatment for primary herpetic gingivostomatitis.
Acvclovir (Zovirax) is effective in the management of initial herpes genitalis.
It is also useful in treating non-lifethreatening mucocutaneous herpes simplex
virus infections in immunocompromised patients (Myers et al., 1982; Whitley et
al., 1982). In these patients a decrease in the duration .of viral shedding has
been reported. There is no reported clinical evidence of benefit in treating
herpes labialis in non-immunocompromised patients.
The usual supportive measures for an acute viral infection
should be instituted. These include maintenance of proper oral hygiene,
adequate fluid intake to prevent dehydration, and the use of systemic
analgesics for control of pain. Antipyretic agents are also prescribed when
fever is a symptom. In severe cases it may be necessary to use a topical
anesthetic mouth rinse such as viscous lidocaine or elixir of diphenhyclramine.
The patient is often able to tolerate cold liquids, and they may aid in
preventing dehydration. Secondary bacterial infection of the many small
punctate ulcers invariably is a major contributor to the pain after the
Herpetic Whitlow is a recognized occupational hazard of dental personnel
and may be contracted through treatment of patients with oral herpetic
lesions. The dentist, hygienist, or assistant in turn, may transmit this
infection to other patients. To prevent this infection, gloves should be
used routinely when examining or treating patients.