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Delusional infestation and the specimen sign: a European multicentre study in 148 consecutive cases
R W Freudenmann1, P Lepping, M Huber
1Department of Psychiatry and Psychotherapy III, University of Ulm, Ulm, Germany.
The British Journal of Dermatology
|May 16, 2012
Summary
Delusional infestation (DI) is a psychiatric condition where patients falsely believe they are infested. This European study found no true infestations among suspected cases, highlighting the need for accurate terminology like "specimen sign."
Area of Science:
- Psychiatry
- Dermatology
- Infectious Diseases
- Medical Entomology
Background:
- Systematic studies on delusional infestation (DI), previously known as delusional parasitosis, are limited, lacking detailed dermatological or psychiatric perspectives.
- There is a significant knowledge gap regarding the characteristics of specimens provided by patients to substantiate their infestation claims.
- Current presentations of DI within Europe have not been adequately studied.
Purpose of the Study:
- To determine the prevalence of genuine infestations in suspected DI cases across European centers.
- To identify the range of pathogens patients believe are causing their infestation.
- To document the frequency, nature, and storage methods of specimens presented as proof of infestation.
Main Methods:
- A retrospective analysis of 148 consecutive suspected delusional infestation cases was conducted.
- Data were collected from six specialized centers (Dermatology, Psychiatry, Tropical Medicine) across four European countries (UK, Germany, Italy, France).
- Inclusion criteria involved patients presenting with symptoms suggestive of infestation, regardless of the suspected etiological agent.
Main Results:
- None of the 148 patients exhibited any evidence of a genuine infestation upon dermatological or infectious disease specialist examination.
- Only 35% of patients believed they were infested by parasites; others suspected diverse living or inanimate pathogens (17%).
- Forty-eight percent of patients presented specimens (mostly skin/hair, rarely insects) as proof; none were linked to a true infestation. The 'matchbox sign' was infrequent, with only 4% of specimens stored in matchboxes.
Conclusions:
- This multicenter European study confirms that 'delusional infestation' is a more fitting term than 'delusional parasitosis' for this condition.
- The presentation of patient-collected specimens, often termed 'the matchbox sign,' is characteristic but not universal in DI.
- The term 'specimen sign' is proposed as a more accurate descriptor for the presentation of proof in delusional infestation cases.
