The skin, more than any other organ, lends itself to disease diagnosis more readily. Most skin lesions can be diagnosed with a simple visual inspection if the eye is clinically well-trained and the patient's history is accurate. There are, however, clinical conditions in which the accurate diagnosis cannot be made at a glance or even after a long period of meticulous observation. In recent years, the introduction of molecular biology tools for pathogen detection and identification has enhanced the speed and accuracy of laboratory diagnosis. These approaches are meant to be used in conjunction with existing microbiologic procedures, not as a replacement for them. The most efficient outcomes come from an integrated analysis of all of them.