Immunohistochemistry in the diagnosis of cutaneous viral infections—part I. Cutaneous viral infections by herpesviruses and papillomaviruses

BACKGROUND: Cutaneous viral infections are of increasing clinical importance, particularly in patients who are immunocompromised.

OBJECTIVE: The use of immunohistochemistry (IHC) in the diagnosis of cutaneous infections provides a rapid morphological diagnosis and can be applied to confirm the diagnosis of specific viral infections that may be difficult to diagnose with certainty using routine microscopy alone, thus facilitating clinical decisions in patient care.

METHODS: Several immunostains for specific viruses that have been useful in dermatopathology are reviewed. Emphasis is placed on new stains and novel uses of existing stains.

RESULTS: This article is an up-to-date overview of the potential uses and limitations of IHC in the histopathologic diagnosis of cutaneous viral infections by herpesviruses and papillomaviruses.

LIMITATIONS: Whereas specific monoclonal antibodies effectively distinguish infections by herpes simplex virus-1, herpes simplex virus-2, varicella zoster virus, Epstein-Barr virus, and cytomegalovirus, IHC does not distinguish between the 120 antigenically distinct strains of human papillomavirus.

CONCLUSIONS: IHC may assist dermatopathologists to appropriately diagnose viral infections caused by herpesviruses and papillomaviruses.