December 2002

4.

5.

6.

Diagnosis: Disseminated Herpes Zoster

Histology: Figure 4 shows the vesicle with mixed inflammatory infiltrate. Figures 5 and 6 more clearly demonstrate cells with viral cytopathic changes, Cowdry type A intranuclear eosinophilic inclusion bodies, and multinucleated giant cells.

Diagnosis: Diagnosis was confirmed with direct immunoflorescence of a scraping from the vesicle base onto a glass slide.

Treatment: The patient was started on IV acyclovir, 10 mg/kg q8 hours for 7 days or until all lesions were resolved. He improved rapidly on this regimen.

Discussion: Herpes zoster infection represents reactivation of the varicella zoster virus from the dorsal ganglia of the spinal cord, where it resides in dormancy after initial infection with varicella. VZV is a double-stranded herpesvirus usually acquired during childhood; a vaccine now exists, which will eventually decrease the number of cases of recurrent zoster as immunized children reach late adulthood. In immunocompetent hosts, zoster activation can lead to blindness from optic nerve involvement, facial hemiplegia, or residual pain, but most commonly resolves without long-term sequela.

Patients who are immunocompromised secondary to cancer (most commonly hematologic), immunosuppressive medications, or HIV have a significantly increased risk of atypical, chronic, and sometimes life-threatening manifestations of zoster reactivation. Dissemination and prolonged viremia are not uncommon in these patients, and they are at increased risk for skin necrosis with scarring, and visceral involvement of the lungs, liver, and brain. Secondary bacterial infection is a not-uncommon complication.

Diagnosis may be made by visualization of a Tzanc smear from a blister base, viral culture, or, where available, ELISA or direct immunoflorescence for VZV.

Disseminated varicella in the immunocompromised patient mandates hospital admission and IV acyclovir 10 mg/kg q8h for 7-10 days. Although zoster in immunocompentent patients is only mildly contagious, isolation precautions should be observed by those not previously exposed to the virus.

References:

Straus SE, Oxman MN. "Varicella and herpes zoster." In: Freedberg IM, Eisen AZ, Wolff K, Austen KF, Goldsmith LA, Katz SI, Fitzpatrick TB, eds. Fitzpatrick's Dermatology in General Medicine. New York: McGraw-Hill, 1999;2427.