Functional itch disorder or psychogenic pruritus is a poorly defined diagnosis. This paper sets out the proposed diagnostic criteria of the French Psychodermatology Group (FPDG). There are three compulsory criteria: localized or generalized pruritus sine materia, chronic pruritus (>6 weeks) and the absence of a somatic cause. Three additional criteria from the following seven items should also be present: a chronological relationship of pruritus with one or several life events that could have psychological repercussions; variations in intensity associated with stress; nocturnal variations; predominance during rest or inaction; associated psychological disorders; pruritus that could be improved by psychotropic drugs; and pruritus that could be improved by psychotherapies.