100 Years of Delusional Parasitosis

Abstract

Delusional parasitosis (DP) is mostly described in single cases or small samples. Data on epidemiology, nosological classification, therapy and course are therefore difficult to interpret. A thorough literature review is recommended to delineate common features of the syndrome. All case reports concerning DP (except toxic forms) were collected and analyzed according to a standardized protocol. DP is a disorder which may occur in every period of life but is much more frequent in older subjects. Sex differences with a predominance of females increase with age. Mean duration of delusion was 3.0 ± 4.6 years (median: 1 year). Social isolation seems to be more a premorbid feature than a secondary phenomenon related to the delusion. Diagnostic classification revealed a high proportion of so-called ‘pure’ forms (‘delusional disorders’ in DSM-III-R or ICD-10) but the syndrome was also reported in schizophrenia, affective or organic psychosis or even as a neurotic symptom. Frequency of induced DP can be estimated between 5 and 15%. Course of DP is not so unfavorable as commonly thought; in about half the patients a full remission was described during the observation period or at catamnesis. Short preclinical courses may indicate better outcome. Comparing the patients of the prepsychopharmacological era (before 1960) with those after, the rate of full remissions increased from 33.9 to 51.9%.

Delusional parasitosis in ENT

“…The prevalence of delusional parasitosis is unknown, but our literature review identifi ed several hundred cases reported by dermatologists and entomologists [11,[13][14][15][16]. It can occur at any age, the average being in the fi fth decade.…”

Delusional Infestation

“…Official and usable results of the CDC study on the search for the unknown pathogen are not available. DI certainly exists, as shown by our historical and epidemiological accounts and uncontradicted psychiatric knowledge over more than 100 years (321,322). However, it is not a psychiatric but a microbiological task to prove or disprove the existence of Morgellons.…”

“…Trabert (321,323) indicated that Robert Willan of London might have discussed cases of DI in his 1799 book. Reviewing the German transcript of the book (343), it appears more likely that the author simply described "pruritus senilis."…”

Ekbom Syndrome: A Delusional Condition of “Bugs in the Skin”

“…Valuable reviews of ES include those by Ekbom [1] (1938), Lyell [11] (1983), Trabert [12] (1995), and Bak et al [7] (2008). Freudenmann and Lepping [2••] have provided an extensive overview of the condition, with discussions of various therapies, including advantages and contraindications.…”

“…For the past 7 years, my office has received two or three ES calls each week. A survey of entomologic colleagues who field ES calls in their states puts the estimate of ES cases in the United States at about 100,000 to 250,000 (rivaling the prevalence of multiple sclerosis) or 10-fold higher than the 1995 estimate by Trabert [12]. Most of the literature on ES consists of case reports; because of the nature of the condition, it is difficult to conduct replicated scientific studies [12,26].…”