In vivo reflectance confocal microscope (RCM) is a high-resolution non-invasive imaging technique that was initially focused on the diagnosis of skin cancers. A rising number of other indications have been later described for the diagnosis and management of inflammatory and infectious dermatological disorders. RCM can identify cutaneous parasites that are not visible to naked eye such as Sarcoptes scabiei and Demodex folliculorum and it allows to better identify the different body parts of bigger parasites such as ticks. Fungal filaments can also be identified as elongated bright structures in the cutaneous upper layers. RCM cannot observe virus directly. However, the cytopathic effect associated with some virus can be recognized. In addition of being helpful for the diagnosis and follow-up after treatment, thanks to its non-invasiveness, RCM allows pathophysiological studies.