Mode of Infection
- As
noted, health
care workers are
at risk due to
possibility of
exposure to virus-containing
secretions from
their patients.
- Patients
with other herpetic
lesions, such
as herpes labialis,
herpetic gingivostomatitis,
or genital herpes,
are at risk due
to autoinoculation.
- Immunocompromised
patients are at
risk for primary
infection, reactivation,
and possibly systemic
complications.
Laboratory
Studies
- Diagnosis
of herpetic whitlow
usually is clinical,
based on presentation
of the affected
digit with characteristic
lesions and a
typical history.
- In
children, observation
of concurrent
gingivostomatitis
is almost pathognomonic.
- In
adults, the presence
of occupational
risk factors or
finding of concurrent
oral or genital
herpes lesions
should strongly
suggest the diagnosis.
- Definitive
diagnostic testing
includes the Tzanck
test, viral cultures,
serum antibody
titres, fluorescent
antibody testing,
or DNA hybridization.
- In
the Tzanck test,
smears are obtained
by scraping
the base of
an unroofed
vesicle. Smears
are Giemsa stained,
and a positive
test is indicated
by light microscopy
findings of
multinucleated
giant cells,
often with visible
viral inclusions.
- Viral
culture of the
aspirated vesicle
fluid is the
most sensitive
assay, but this
test is usually
more costly
and time consuming,
requiring 24-48
hours.
- Serum
antibody titres
are usually
cost prohibitive,
as are fluorescent
antibody testing
and DNA hybridization,
which are not
commonly available.
Emergency
Department Care:
- Herpetic
whitlow is a self-limiting
disease. Treatment
is mostly directed
toward symptomatic
relief.
- Tense
vesicles may be
unroofed to help
ameliorate symptoms,
and wedge resection
of the fingernail
may be used for
the same purpose
in cases involving
the subungual
space.
- Deep
surgical incision
is contraindicated,
since this may
lead to delayed
resolution, bacterial
superinfection
or systemic spread,
and complications
such as herpes
encephalitis.
Follow
up Care
- Advise
routine outpatient
follow up care
to ensure resolution
of infection and
to monitor for
evidence of bacterial
super infection.
In/Out
Patient Medicines
- Include
analgesics in
the treatment
of herpetic whitlow.
- Antivirals
may be of benefit
in primary infections.
- In
cases of super
infection, antibiotics
are effective
against skin pathogens.
Deterrence/Prevention
- Avoidance
of exposure is
the key to prevention
of herpetic whitlow.
- Health
care workers
should use gloves,
practice strict
hand washing,
and scrupulously
observe universal
fluid precautions.
- Studies
have demonstrated
herpes virus
in 2.5% of asymptomatic
patients and
in 6.5% of hospitalized
patients with
tracheostomies.
- Patients
with oral, labial,
or genital lesions
and the parents
and caregivers
of children with
lesions should
be cautioned against
digital contact
with lesions.
- Complications
usually are minimal
provided that
the affected patients
are immunocompetent.
- Misdiagnosis
as a bacterial
paronychia or
felon with resultant
deep incision
may lead to delayed
resolution, increased
risk of bacterial
superinfection,
systemic spread
(rare), and possibly
development of
herpes encephalitis.
- Hyperesthesia
or numbness has
been reported
in 30-50% of patients
between episodes
of reactivation.
- Other
potential complications
include scarring
of the affected
digit and ocular
spread.
Prognosis
- Prognosis
is excellent in
uncomplicated
cases, with spontaneous
resolution in
3-4 weeks.
Patient
Education
- Advise
patients of the
likelihood of
future recurrence
and warn of the
possibility of
disease spreading
to other parts
of the body and
to other individuals.
Medical/Legal
Pitfalls
- Misdiagnosis
and inadvertent
deep incision
may result in
delayed healing,
increased risk
of bacterial superinfection
or systemic spread,
and possibly herpes
encephalitis.
Herpetic
whitlow is an infection
of the finger by the
herpes simplex virus
(HSV). Herpetic whitlow
is typically caused
by HSV-1, the type
that generally causes
oral herpes. Herpes
can infect any site
on the skin, but the
finger is probably
the most common. Children
newly infected with
oral herpes can spread
it to their thumbs
during sucking. In
adults, it also can
be spread from an
oral lesion, almost
always after a primary
(new) infection rather
than recurrences.
Health care workers
such as dental hygienists
frequently develop
herpetic whitlow after
caring for patients
with oral herpes.
A person infected
with HSV can transmit
it to others even
if he or she has no
active lesions, so
you may have contracted
it from any one of
your patients. This
infection is just
one more reason to
wear gloves with every
single patient.
Unlike oral and genital
herpes, which the
infected person can
transmit even when
he or she has no visible
lesions, herpetic
whitlow probably is
less likely to spread
in the absence of
lesions. One is probably
contagious as long
as one has a wet,
open lesion. Since
it is only on the
finger, it is probably
not infectious as
long as gloves are
worn. Herpetic whitlow
can recur, though
usually not as often
as do oral or genital
herpes.
As far as a baby is
concerned, herpetic
whitlow in the mother
is not really a cause
to worry too much.
It is genital herpes
that causes most of
the problems for newborns.
Women who become infected
shortly before delivery
and have genital lesions
at the time of delivery
are most likely to
transmit the infection
to the baby, although
individuals with recurrent
herpes lesions also
can infect the baby
during delivery.
Far
less common is infection
during pregnancy,
long before delivery.
Infection of the fetus
can result in stillbirth
and congenital anomalies.
Most of the data on
transmission to the
fetus involve genital
herpes, not oral herpes.
How the Infection
Develops
After
an incubation period
of 2 to 14 days, the
patient may experience
prodromal symptoms,
such as fever and
malaise. Common initial
symptoms of infection
include tingling pain
or tenderness in the
affected digit, followed
by throbbing pain,
swelling, and redness.
Vesicles, which form
over the next week,
contain fluid that
may be clear, bloody,
or cloudy. While these
vesicles are present,
herpetic whitlow is
extremely contagious.
About
2 weeks after vesicles
first appear, a crust
forms over them. This
signals the end of
viral shedding.
If
untreated, the infection
usually resolves in
3 to 4 weeks. Treatment
with antiviral medication
may speed healing
and reduce viral shedding,
but some patients
never regain full
sensitivity or range
of motion in the digit.
Herpetic
whitlow vesicles are
susceptible to secondary
bacterial infections.
Signs and symptoms
of a secondary infection
include fever, chills,
red streaks the length
of the arm, lymphadenopathy,
and fatigue.
After
healing, about 20%
to 50% of the patients
experience recurrences,
which may be triggered
by trauma, febrile
illness, disease,
or other physiologic
changes. The recurrence
usually is milder
and clears up faster
than the original
infection.
The health care provider
will base her diagnosis
on signs and symptoms
and confirm it with
lab testing Options
include isolating
the virus from a sample
of vesicular fluid,
a Tzanck test (a stain
histology test), and
serum immunoglobulin
antibody testing for
HSV IgM (to detect
acute HSV) and IgG
(to detect a history
of HSV).
Treatment and Prevention
To
treat herpetic whitlow,
the health care provider
will order an oral,
topical, or I.V. antiviral
medication. These
medications accelerate
healing, reduce viral
shedding and pain,
and may help prevent
a recurrence. Prescriptions
for secondary infection
may be given, if indicated.
Incision and drainage
of vesicles isn't
indicated because
this may spread the
infection. |
