[Parasitic delusions: literature review and report of new cases].

Delusion of parasitosis is an unshakeable conviction that small organisms or parasites infest the body even though there is no confirmative physical evidence. Since 1938, when K.A. Ekbom described and named "Dermatozoenwahn" for the first time, this clinical feature has focussed the interest of researchers due to the uncertainty on its nosologic classification. We report three cases of delusions of parasitosis in patients who suffered from schizophrenia, monosymptomatic hypochondriacal psychosis and major depression with psychotic features respectively. We throw into relief the essential aspects of aetiology, treatment and nosologic classification of the syndrome.