Abstract: The identification of pathogens is of vital importance for the adequate treatment of infections. During the past 2 decades, the approach to histopathologic diagnosis has been dramatically transformed by immunohistochemistry (IHC) specifically in the diagnosis and classification of tumors and more recently in the diagnosis of infectious diseases in tissue samples. The main goals of this article were to: (1) identify by IHC the cutaneous structures where bacterial pathogens are expressed in the course of infection, (2) identify the specific cells in which bacterial pathogens are expressed in positive cases, and (3) describe the pattern of distribution of the bacterial antigens within these cells (nuclear, cytoplasmatic, or membranous). This article is an up-to-date overview of the potential uses and limitations of IHC in the histopathologic diagnosis of cutaneous bacterial infections. In conclusion, IHC is especially useful in the identification of microorganisms that are present in low numbers, stain poorly, are fastidious to grow, culture is not possible, or exhibit an atypical morphology.
*Associate Professor of Dermatology and Dermatologist (Dr Molina-Ruiz), Chairman and Professor of Dermatology (Dr Requena), Department of Dermatology, Fundación Jiménez Díaz, Universidad Autónoma, Madrid, Spain;
†Director of Dermatopathology and Professor of Dermatology, Department of Dermatology, Medical University of Graz, Graz, Austria;
‡Director of Dermatopathology Laboratory, Dermatopathologisches Gemeinschaftslabor of Friedrichshafen, Germany.
Reprints: Luis Requena, MD, Department of Dermatology, Fundación Jiménez Díaz, Avenida Reyes Católicos 2, Madrid 28040, Spain (e-mail: lrequena@fjd.es).
All authors and staff in a position to control the content of this CME activity and their spouses/life partners (if any) have disclosed that they have no financial relationships with, or financial interests in, any commercial organizations pertaining to this educational activity.
