Varicella Zoster Virus VZV (Chickenpox)

Varicella: Highly contagious primary infection caused by (varicella zoster virus), characterized by successive crops of pruritic vesicles that evolve pustules, crusts, and at times, scars, and is often accompanied by mild constitutional symptoms; primary infection occurring in adulthood may be complicated by pneumonia and encephalitis

Epidemiology:

Age: 90% of cases occur in children <10 years. Transmission: airborne droplets as well as direct contact; indirect contact uncommon. Patients are contagious several days before exanthema appears and until last crop of vesicles. Crusts are not infectious.

Season: in metropolitan areas in temperature climates, varicella epidemics occur in winter and spring.

Geography: Worldwide

History & Physical Examination

Incubation period: 14 days (range 10 to 23 days)

Prodrome: characteristically absent or mild. Uncommon in children, more common in adults: headache, general aches and pains, several backache, malaise. Exanthem appears within 2-3 days.

History Exposure at day care, school, to older siblings; relative with zoster

Skin Lesions: In most children, illness begins with appearance of exanthema, vesicular lesions evident in successive crops. Often single, discrete lesions or scanty in number in children, and more dense in adults.

Distribution: First lesions begin on face and scalp, spreading inferiorly to trunk and extremities. Most profuse in areas least exposed to pressure, i.e. back between shoulder blades, flanks, axilae, popliteal and anticubital fossae.
Density highest on trunk and face, less on extremities. Palms and soles usually spared.

Mucous Membranes: vesicles (not often observed) and subsequent shallow erosions (2-3mm) most common on palate but also occur on mucosa of nose, conjunctivae, pharynx, larynx, trachea, gastrointestinal tract (*vesiculopustules may occur in GIT), urinary tract, vagina.

Course and Prognosis

In healthy children, the course is self-limited; however, a mortality rate of 1 per 50,000 cases in United States is reported.

Maternal varicella during the first trimester of pregnancy may result in fetal varicella syndrome (limb hypoplasia, eye and brain damage, skin lesions) in 2% of exposed fetuses.

In immunocompromised individuals, VZV hepatitis is relatively common and is associated with significant mortality.

Management:

Prevention:
VZV immunization (Varivax) and is 80% effective in preventing symptomatic primary VZV infection, 5% of newly immunized children develop rash. Those at high risk of varicella who should be immunized, include:

• normal adults
• children with leukemia
• neonates in utero
• and immunocompromised patients

Patients should be isolated from non-immunocompromised patients.

Treatment:
Oral Acyclovir
Symptomatic treatment of pruritus
Treatment of bacterial superinfection

Outbreak of Varicella Zoster Virus (VZV) Chickenpox in Dahab

In 2012 we have seen unusual outbreak of VZV in a sporadic form, affecting predominant children below the age of 10.

Over a period of 2 months, there were 3 waves of outbreaks, the last which, developed the most severe symptoms:

• First Outbreak: began at the end of February 2012 and last for approximately 2 weeks, affecting children below the age of 10.
• Second Outbreak: began one month later and lasted for the same amount of time, also affecting children under the age of 10, though included a few Bedouin adults.
• Third Outbreak: occurred at the end of April after a 2 week period of absence and strangely 60% of the cases were above the age of 20.

The third outbreak cases presented with similar but more serious VZV symptoms as previous, but also suffered severe abdominal pain, diarrhea as well as high fever.

Clinical diagnosis revealed GIT (Visceral) developed symptoms of vesicles and shallow erosions within the intestines which were treated effectively with systemic anti-viral therapy.

Since 1998, I have not seen any outbreak of VZV in waves in South Sinai. Outbreaks that I have seen have occurred earlier in the year and have lasted no longer than 2 weeks.

I believe that this unusual pattern and presentation of VZV could be related to the changes of climate in the region.

I advise women within the first trimester of pregnancy to take extra care -apart of these women, there is no need for paranoia and no need to remove children from their daily activities, if their behavior is normal.

Cases presented within the first 24hrs of sickness are effectively treated with local anti-viral cream which helps to reduce symptoms. treating within the first 24 hrs helps to ensure we have no complicated cases or encephalitis.

REFERENCES:
Fitzpatric clinical Dermatology, 3rd edition.
Ball/Gray. Infectious Diseases