Polymerase chain reaction-based molecular diagnosis of cutaneous infections in dermatopathology.

Conventional methods, including microscopy, culture, and serologic studies, are a mainstay in the diagnosis of cutaneous infection. However, owing to limitations associated with these techniques, such as low sensitivity for standard microscopy and in the case of culture delay in diagnosis, polymerase chain-reaction based molecular techniques have taken on an expanding role in the diagnosis of infectious processes in dermatopathology. In particular, these assays are a useful adjunct in the diagnosis of cutaneous tuberculosis, atypical mycobacterial infection, leprosy, Lyme disease, syphilis, rickettsioses, leishmaniasis, and some fungal and viral infections. Already in the case of tuberculosis and atypical mycobacterial infection, standardized polymerase chain-reaction assays are commonly used for diagnostic purposes. With time, additional molecular-based techniques will decrease in cost and gain increased standardization, thus delivering rapid diagnostic confirmation for many difficult-to-diagnose cutaneous infections from standard formalin-fixed paraffin-embedded tissue specimens.