title: Delusional infestation and the specimen sign: a European multicentre study in 148 consecutive cases.
abstract: BACKGROUND
  Systematic studies of delusional infestation (DI), also known as delusional parasitosis, are scarce. They lack either dermatological or psychiatric detail. Little is known about the specimens that patients provide to prove their infestation. There is no study on the current presentation of DI in Europe.
  
  
  OBJECTIVE
  To determine the number of true infestations, to assess with which pathogens patients believe themselves to be infested, and to gather details about the frequency and nature of the specimens and the containers used to store them, based on European study centres.
  
  
  METHODS
  Retrospective study of consecutive cases with suspected DI from six centres (Dermatology, Psychiatry, Tropical Medicine) in four European countries (U.K., Germany, Italy, France).
  
  
  RESULTS
  In total, 148 consecutive cases of suspected DI were included, i.e. the largest cohort reported. None of the patients had evidence of a genuine infestation, as shown by examinations by dermatologists and/or infectious disease specialists. Only 35% believed themselves to be infested by parasites; the majority reported a large number of other living or inanimate (17%) pathogens. Seventy-one patients (48%) presented with what they believed was proof of their infestation. These specimens were mostly skin particles or hair, and rarely insects (only very few of which were human pathogenic or anthropophilic, and none of these could be correlated with the clinical presentation), and only 4% were stored in matchboxes (three of 71).
  
  
  CONCLUSIONS
  This first multicentre study of DI in Europe confirms that the term 'delusional infestation' better reflects current and future variations of this entity than 'delusional parasitosis'. The presentation of proofs of infestation, commonly referred to as 'the matchbox sign', is typical but not obligatory in DI and might better be called 'the specimen sign'.
authors.affiliation: Department of Psychiatry and Psychotherapy III, University of Ulm, Ulm, Germany.
authors.forename: R W
authors.initials: RW
authors.lastname: Freudenmann
authors.forename: P
authors.initials: P
authors.lastname: Lepping
authors.forename: M
authors.initials: M
authors.lastname: Huber
authors.forename: S
authors.initials: S
authors.lastname: Dieckmann
authors.forename: K
authors.initials: K
authors.lastname: Bauer-Dubau
authors.forename: R
authors.initials: R
authors.lastname: Ignatius
authors.forename: L
authors.initials: L
authors.lastname: Misery
authors.forename: M
authors.initials: M
authors.lastname: Schollhammer
authors.forename: W
authors.initials: W
authors.lastname: Harth
authors.forename: R E
authors.initials: RE
authors.lastname: Taylor
authors.forename: A P
authors.initials: AP
authors.lastname: Bewley
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003702:Delusions / Q000469:parasitology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012876:Skin Diseases, Parasitic / Q000523:psychology*; D013048:Specimen Handling