Rapid detection and distinction of cutaneous herpesvirus infections by direct immunofluorescence.

BACKGROUND Optimal management of cutaneous herpes simplex virus (HSV) and varicellazoster virus (VZV) infections requires rapid, accurate distinction between these pathogens. OBJECTIVE In a mixed-case series of suspected cutaneous herpesvirus infections, we compared the diagnostic utility of viral culture and direct immunofluorescence (DIF) using a panel of fluoresceinated monoclonal antibodies against HSV and VZV. METHODS Epifluorescence microscopy of smears and viral culture were performed in parallel on 58 lesions. RESULTS DIF and culture were equally sensitive (88%) in HSV infections, whereas DIF was four times as sensitive as culture (100% vs 18%) in VZV. DIF either refuted an incorrect clinical diagnosis or permitted definitive laboratory diagnosis of a clinically indeterminate lesion in 7 (12%) of 58 lesions tested. CONCLUSION DIF is a rapid, simple, sensitive, specific, cost-effective, and clinically useful technique for detecting and distinguishing cutaneous HSV and VZV infections.