Herpes simplex virus
A range of infections, mainly viral, can produce oral
blistering, but most patients present with ulceration after the blisters break.
Herpesviruses are frequently responsible (Figure 9.1). Affected patients are
largely children and there is often fever, malaise and cervical
lymphadenopathy.
More severe manifestations and recalcitrant lesions
are seen in immunocompromised people.
Herpes simplex
Definition: Herpes simplex virus (HSV) infection is
common and affects mainly the mouth (HSV-1 or human herpesvirus-1; HHV-1), or
genitals or anus (HSV-2; HHV-2). Initial oral infection presents as primary
herpetic stomatitis (gingivostomatitis). All herpesvirus infections are
characterized by latency (Figure 9.2), and can be reactivated. Recurrent
disease usually presents as herpes labialis (cold sore).
Prevalence (approximate): Common. Age mainly affected:
Herpetic stomatitis is typically a childhood infection seen between the ages of
2–4 years, but cases are increasingly seen in the mouth and/or pharynx in older
patients.
Gender mainly affected: M : F.
Etiopathogenesis: HSV, a DNA virus, is
contracted from infected skin, saliva or other body fluids. Most childhood
infections are with HSV-1, but HSV-2 is often implicated more often at later
ages, often transmitted sexually. UNC-93B1 gene mutations predispose to
herpesvirus infection.
Diagnostic features
History: The incubation period is 4–7 days. Some 50%
of HSV infections are subclinical and may be thought to be “teething” because
of oral soreness.
Clinical features: Primary stomatitis
presents with a single episode of multiple oral vesicles which may be
widespread, and break down to form ulcers that are initially pinpoint but later
fuse to produce irregular painful ulcers (Figure 9.3). Gingival edema, erythema
and ulceration are prominent (Figure 9.4). The tongue is often coated and there
may be oral malodor.
Herpetic stomatitis probably explains many instances
of “teething”.
Extraoral features: Commonly include malaise,
drooling, fever and cervical lymph node enlargement.
Complications of HSV infection occasionally include
erythema multiforme or Bell palsy. HSV-1 appears to increase the risk of
developing Alzheimer disease. Rare complications include meningitis, encephalitis
and mononeuropathies, particularly in people with impaired immunity, such as
infants whose immune responses are still developing, or immunocompromised
patients.
Differential diagnosis:
Other oral infections and leukemic gingival infiltrates.
Investigations: The diagnosis is largely
clinical but blood tests to exclude leukemia (full blood picture and white cell
count) may be indicated, and a rising titer of serum antibodies is
diagnostically confirmatory but only retrospectively. Cytology, viral DNA
sequentiation, culture, immunodetection or electron microscopy are used
occasionally (Figures 9.5a–c).
Management
Treatment aims to limit the severity and duration of
pain, shorten the duration of the episode, and reduce complications. Management
includes a soft diet and adequate fluid intake. Antipyretics/analgesics such as
paracetamol help relieve pain and fever. Products containing aspirin must not
be given to children with any fever-causing illness suspected of being of viral
origin, as this risks causing the serious and potentially fatal Reye syndrome
(fatty liver plus encephalopathy).
Local antiseptics (0.2% aqueous chlorhexidine
mouthwashes) may aid resolution. Aciclovir orally or parenterally is useful
especially in immunocompromised patients. Valaciclovir or famciclovir may be
needed for aciclovir-resistant infections.
Prognosis
Good, though HSV remains latent thereafter in the
trigeminal ganglion and recurrences may occur.
Recurrent herpes labialis
Definition: Recurrent blistering of the lips caused by
HSV reactivation. Prevalence (approximate): 5% of adults.
Age mainly affected: Adults.
Gender mainly affected: M = F.
Etiopathogenesis: HSV latent in the trigeminal
ganglion travels to mucocutaneous junctions supplied by the trigeminal nerve,
producing lesions on the upper or lower lip, occasionally the nares or the
conjunctiva or, occasionally intraoral ulceration. Fever, sunlight, trauma,
hormonal changes or immunosuppression can reactivate the virus which is shed
into saliva, and there may be clinical recrudescence.
Diagnostic features
History: Oral premonitory symptoms may be tingling or
itching sensation on the lip in the day or two days before, followed by
appearance of macules, then papules, vesicles and pustules.
Clinical features: Oral lesions start at the
mucocutaneous junction and heal usually without scarring in 7–10 days (Figure
9.6). Widespread recalcitrant lesions may appear in immunocompromised patients.
Extraoral: Occasionally lesions become superinfected
with Staphylococcus or Streptococcus, resulting in impetigo. In
immunocompromised persons, extensive and persistent lesions may involve the perioral
skin. In atopic persons, the lesions of herpes labialis may spread widely to
produce eczema herpeticum.
Differential diagnosis:
Impetigo and other causes of blisters.
Investigations are rarely needed as the diagnosis is
largely clinical.
Management
Penciclovir 1% cream, aciclovir 5% cream or silica gel
applied in the prodrome may help abort or control lesions in healthy patients. Systemic
aciclovir or other antivirals may be needed for immunocompromised patients.
Prognosis
Usually good but immunocompromised patients can
develop recalcitrant lesions.
Recurrent intraoral herpes
Recurrent intraoral herpes in healthy patients tends
to affect the hard palate or gingiva, as a small crop of ulcers usually over
the greater palatine foramen, following local trauma (e.g. palatal local
anesthetic injection), and heals within 1–2 weeks.
Recurrent intraoral herpes in immunocompromised patients
may appear as chronic, often dendritic, ulcers frequently on the
tongue ( herpetic geometric glossitis). Clinical diagnosis tends to
underestimate the frequency of these lesions.
Management: The aims are to limit
the severity and duration of pain, shorten the duration of the episode, and
reduce complications. Symptomatic treatment with a soft diet and adequate fluid
intake, antipyretics/analgesics (paracetamol), local antiseptics (0.2% aqueous chlorhexidine
mouthwashes) usually suffices. Systemic aciclovir or other antivirals may be
needed for immunocompromised patients.
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