“Morgellons disease” has been a controversial topic in the history of psychodermatology. The most consensual scientific opinion is that it is a primary psychiatric disorder, particularly, a delusional disorder, although others were also pointed out. Some authors have suggested that it may correspond to a common dermatosis with secondary psychopathology. The Morgellons Research Foundation has advocated that it is “an emerging infectious” entity. This paper intends to critically review the main ideas and controversies, since its first description.