Njm4/19/04

**What should I do about a patient at 4-6 weeks gestation with a
varicella like rash?**

As luck would have it, only 5% of pregnant women who had no history of
varicella are susceptible, using fluorescent antibody to
varicella-zoster virus (VZV) membrane antigen to measure antibody
status.

On the other hand, to evaluate those 5%, the diagnosis of varicella is
usually made clinically. VZV may be cultured from vesicular fluid, but
this is a cumbersome process. Serologic tests may help document acute
infection in confusing cases or indicate immunity. IgM antibody may be
detected as soon as three days after VZV symptoms appear, and IgG may be
detected as early as seven days after varicella symptoms. Multiple
antibody detection assays are available including fluorescent
anti-membrane antibody (FAMA), latex agglutination (LA), enzyme-linked
immunosorbent assay (ELISA), and complement fixation tests.

Depending on your lab's turn around time, serologic testing is often not
initially helpful. As acyclovir has not been shown to be helpful to
treat the fetus in utero, its use is confined to decrease the severity
of the maternal disease by 1-2 days, if initiated within the first 24
hours of rash onset. Treatment with acyclovir from 25 to 72 hours after
the appearance of the rash had no effect on the course of the illness.

There is no role for VARIVAX, a live attenuated vaccine, in pregnancy
and once active varicella is diagnosed in the mother, V.Z.I.G. is of no
proven benefit.

Congenital varicella has an incidence of 2% and often confined to two
scenarios: 1.) congenital varicella syndrome cases occur in infants
whose mothers were infected between 8 and 20 weeks of gestation 2.)
neonates born to mothers who are exposed to VZV or have clinical disease
manifestations within two weeks of delivery are at the greatest risk for
infection. Neonatal varicella is a serious illness associated with up to
a 25 percent mortality rate. Nosocomial acquisition of VZV has been
reported.

Prenatal diagnosis of fetal varicella infection is possible.
Ultrasonography can detect limb abnormalities in affected fetuses. In
other studies, fetal blood has been obtained via percutaneous blood
sampling for VZV antibody or DNA on blood or amniotic fluid. Although
serologic methods can identify VZV infection early in fetal development,
they cannot predict sequelae from VZV infection.

The mother should be carefully monitored for the development of
varicella pneumonia. Varicella pneumonia in pregnancy is a medical
emergency. The mortality rate in untreated pregnant women is in excess
of 40 percent. Varicella pneumonia is seen in up to 20 percent of adult
chickenpox cases. Retrospective studies suggest that varicella pneumonia
may be more severe, although not more frequent, in pregnant compared to
nonpregnant women.

For the rest of the story please see these resources.

**Perinatology Corner Module: Chickenpox (varicella) in pregnancy (Free
CME/CEU)**

[[http://www.ihs.gov/MedicalPrograms/MCH/M/VC01.cfm]{.underline}](http://www.ihs.gov/MedicalPrograms/MCH/M/VC01.cfm)

**Varicella-zoster virus infection in pregnancy: UpToDate**

[[http://www.uptodateonline.com/application/topic.asp?r=/application/topic.asp&file=viral_in/4765&app=utdol]{.underline}](http://www.uptodateonline.com/application/topic.asp?r=/application/topic.asp&file=viral_in/4765&app=utdol)

**Treatment and prevention of chickenpox: UpToDate**

[[http://www.uptodateonline.com/application/topic.asp?file=viral_in/11333]{.underline}](http://www.uptodateonline.com/application/topic.asp?file=viral_in/11333)

**Exposure algorithm**

<http://www.uptodateonline.com/application/image.asp?file=id_pix/rx_varic.gif>

**Acylcovir: UpToDate**

[[http://www.uptodateonline.com/application/topic.asp?file=drug_a_k/7496&drug=true]{.underline}](http://www.uptodateonline.com/application/topic.asp?file=drug_a_k/7496&drug=true)