Delusions of parasitosis: a brief review of the literature and pathway for diagnosis and treatment.

A large proportion of patients seen in dermatology practices have underlying psychological issues associated with their skin diseases. One of the most flagrant examples of this are patients with delusions of parasitosis. These patients have false fixed beliefs that they are infested by parasites and experience cutaneous sensations of crawling, biting, and stinging associated with their delusions. There is no organic skin disorder and all cutaneous manifestations are self-induced. Rather than a psychiatrist, the dermatologist is often designated by the patient to handle the chief complaint, even though the main disorder is psychogenic. In spite of their limited evidence, antipsychotic medications have become the mainstay of therapy for delusions of parasitosis. The dermatologist must therefore be familiar with the approach to diagnosis and the use of antipsychotic or neuroleptic medications, which usually reside in the domain. There are few clinical trials and no substantial randomized controlled trials examining the efficacy of the psychiatrist antipsychotic medication used to treat delusions of parasitosis. This review article synthesizes the current available research and distils it down to analyzes 17 case reports, comprising 37 cases, examining the use of risperidone and olanzapine in the treatment of delusions of parasitosis. These findings are synthesized into a clinical pathway designed to assist dermatologists in effectively managing patients with delusions of parasitosis.

[Delusional parasitosis intestinal and dermatological: clinical cases]. / Parasitosis ilusoria intestinal y dermatológica: casos clínicos.

Illusory parasitosis, better known as delusional parasitosis, is a neuropsychiatric syndrome in which patients have the belief of suffering a parasitic disease, that can not be demonstrated after an exhaustive medical study. These patients are characterized by being polyconsultants in different medical specialties and, many of them, have antecedents of psychiatric disorders, some of them undiagnosed. Knowing the existence of the clinical picture, diagnosing early and empathizing with the patient, could give to clinician some clues for a timely and assertive psychiatric referral, and improve patient adherence to the proposed treatment.

What's eating you? minute brown scavenger beetle.

Patients with delusional infestation frequently bring specimens and examining these specimens is important in establishing a therapeutic relationship. The minute brown scavenger beetle is a member of the family Latridiidae. It is found in moist environments and feeds on mold. It poses no threat to humans, but it is important that dermatologists recognize it because it may be contained in specimens brought by patients.

Parasitosis ilusoria intestinal y dermatológica: casos clínicos / Delusional parasitosis intestinal and dermatological: clinical cases

Illusory parasitosis, better known as delusional parasitosis, is a neuropsychiatric syndrome in which patients have the belief of suffering a parasitic disease, that can not be demonstrated after an exhaustive medical study. These patients are characterized by being polyconsultants in different medical specialties and, many of them, have antecedents of psychiatric disorders, some of them undiagnosed. Knowing the existence of the clinical picture, diagnosing early and empathizing with the patient, could give to clinician some clues for a timely and assertive psychiatric referral, and improve patient adherence to the proposed treatment.

La parasitosis ilusoria, más conocida como delusión parasitaria, es un síndrome neuropsiquiátrico donde los pacientes tienen el convencimiento de padecer una infestación parasitaria, que no puede ser demostrada tras un exhaustivo estudio médico. Estos pacientes se caracterizan por ser policonsultantes en distintas especialidades médicas y, muchos de ellos, poseen antecedentes de trastornos psiquiátricos, algunos de ellos no diagnosticados. Conocer la existencia del cuadro, diagnosticar precozmente y empatizar con el paciente, pueden dar al médico clínico algunas claves para una derivación psiquiátrica oportuna y asertiva, y mejorar la adherencia del paciente al tratamiento propuesto. Se presentan cuatro casos clínicos que consultaron por esta extraña condición.

Delusional infestation may be caused by recreational drug usage in some patients, but they may not disclose their habit.

BACKGROUND: Patients with delusional infestation (DI) believe that their skin is infested with organisms or inanimate particles, despite objective evidence to the contrary. Previous studies indicate a higher rate of recreational drug use among patients with DI. It is known that symptoms of infestation such as formication can be secondary to use of recreational drugs and alcohol. We carried out a pilot study observing the prevalence of recreational drug use in patients with DI. AIM: To observe the prevalence of recreational drug use in patients with DI. METHODS: A retrospective review of 86 consecutive patient records was carried out over a 3-year period (1 March 2012 to 1 March 2015) to determine current or previous recreational drug use. Additionally, 24 consecutive patients with DI attending clinic between 1 December 2014 and 1 March 2015 were prospectively offered a urine test for recreational drugs. RESULTS: Of the 86 patients, 19 had recreational drug use documented in their medical notes (22.1%). Of the 24 patients offered a urine test, 18 accepted (75%); the remaining 6 patients agreed to provide a urine sample immediately after consultation, but did not do so. Of the 18 samples collected, 6 were positive (33.3% of completed tests) for recreational drugs. Cannabis was the most commonly used drug. CONCLUSIONS: This study indicates that the prevalence of recreational drug use in patients with DI is high, and that patients do not always disclose their habit. It is hoped that this pilot study will lead to further research into this finding.

Sensations of skin infestation linked to abnormal frontolimbic brain reactivity and differences in self-representation.

Some patients experience skin sensations of infestation and contamination that are elusive to proximate dermatological explanation. We undertook a functional magnetic resonance imaging study of the brain to demonstrate, for the first time, that central processing of infestation-relevant stimuli is altered in patients with such abnormal skin sensations. We show differences in neural activity within amygdala, insula, middle temporal lobe and frontal cortices. Patients also demonstrated altered measures of self-representation, with poorer sensitivity to internal bodily (interoceptive) signals and greater susceptibility to take on an illusion of body ownership: the rubber hand illusion. Together, these findings highlight a potential model for the maintenance of abnormal skin sensations, encompassing heightened threat processing within amygdala, increased salience of skin representations within insula and compromised prefrontal capacity for self-regulation and appraisal.

[Delusional infestation, a therapeutic challenge]. / Parasieten- of infestatiewaan: een therapeutische uitdaging.

Delusional infestation, formally known as delusional parasitosis, poses a therapeutic challenge. This article provides tools to engage these patients with psychiatric treatment. We present two men aged 49 and 48 who saw the dermatologist with skin symptoms due to primary and secondary delusional infestation, respectively. Despite their anosognosia, both patients were successfully treated with antipsychotics thanks to the collaboration between dermatology and psychiatry. To increase the acceptability of treatment with antipsychotics, emphasis should be placed on their antipruritic properties and the effect on degree of preoccupation with the infection rather than their antipsychotic properties. Follow-up is important, as patients mostly do not attribute their recovery to antipsychotics and the risk of recurrence is high after cessation of antipsychotic medication.

Delusions of parasitosis.

The most common monosymptomatic hypochondriacal psychosis encountered by a dermatologist is delusions of parasitosis. In this condition, patients have an "encapsulated" fixed, false belief that they are infested with parasites or have foreign objects extruding from their skin. The patient will often experience feelings of biting, crawling and stinging related to the delusion. Most patients do not have other major psychiatric problems outside of their encapsulated delusion. The patient usually presents with a long history of symptoms and multiple visits to physicians in more than one specialty. Without an informed approach to these patients that focuses on the development of therapeutic alliance, clinical interactions can become very unpleasant. However, when treated with pimozide, risperidone, or other antipsychotic medications, patients have a very high response rate. Therefore, it is important for dermatologists to be able to handle these cases and know that the development of the therapeutic alliance is the key step to successful management.

Delusional infestation and the specimen sign: a European multicentre study in 148 consecutive cases.

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. OBJECTIVES: 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'.

Delusional parasitosis: a rare cause of pruritus in hemodialysis patients.

Uremic pruritus is a common symptom in patients undergoing hemodialysis (HD) or peritoneal dialysis, but its exact pathogenesis remains rather unclear. However, severe or "intractable" pruritus may be the manifestation of another underlying disease or disorder other than uremia. Delusional parasitosis, or Ekbom syndrome, is a rare psychiatric disorder characterized by the false conviction of being infested with parasites, and it can be primary, or secondary to several medical and psychiatric disorders. We report 2 elderly HD patients who presented one after another, with delusional parasitosis. At some point in time, the delusional beliefs of the first patient were adopted by the second patient who was waiting to start his HD session on the same bed and HD machine, on a subsequent shift. They were both diagnosed with Ekbom syndrome and described as having monosymptomatic hypochondriac delusion. They were both prescribed antipsychotic medications. During follow-up they admitted feeling better than before; however, they remained concerned about the "insects/parasites."

Delusion of parasitosis: case report and current concept of management.

Delusions of parasitosis (DP) is a primary psychiatric disorder, a type of monosymptomatic hypochondriac psychosis in which patients believe that 'bugs' or 'parasites' have infested their skin or that they have even spread into their visceral organs. Patients with DP usually approach different medical specialists, mostly dermatologists and primary care physicians because of symptoms presenting as crawling under their skin. Therefore, the exact prevalence of DP is unknown. It is believed that it is a rare disorder but different studies indicate that the prevalence is greater than presented. The etiology of this disorder is still unclear. Patients with DP come to a physician with a stereotypic history. Usually the patient has previously addressed many other different specialists and symptoms are usually present for several months to years. The main cutaneous symptom is crawling, biting and pruritus due to 'burrowing of parasites, insects or bugs' under the skin. Patients with DP are rare but can be very challenging for making the correct diagnosis and for the treatment as well. It is essential to distinguish primary from secondary disorder since the approach to these patients is different. Dermatologists who have good knowledge in diagnosis, both dermatologic and psychodermatologic, and who dare prescribe antipsychotics after consulting liaison-psychiatrist, can have good results in treating patients with DP. When treating patients with DP, multidisciplinary approach by collaboration between a dermatologist and a psychiatrist is necessary to provide complete and meaningful treatment for these patients.

Patients with delusional infestation (delusional parasitosis) often require prolonged treatment as recurrence of symptoms after cessation of treatment is common: an observational study.

BACKGROUND: Delusional infestation (DI) is an uncommon psychiatric disorder in which patients present with the false and fixed belief of infestation. Numerous studies have demonstrated improvement with pharmacological treatment; however, recurrence rates on cessation of treatment remain unknown. OBJECTIVES: To assess the clinical response and recurrence rates following treatment for DI. METHODS: All patients with DI seen in our combined dermatology/psychiatry clinic to date (n=73) were offered pharmacological therapy. Patients were contacted to complete a telephone questionnaire to assess clinical outcomes, including remission and recurrence rates following treatment. RESULTS: Fifty-nine of 73 (81%) patients with DI received treatment, of whom 40/59 (68%) reported improvement or resolution of symptoms, and the remaining 19/59 (32%) failed to respond. Fifteen of 40 patients with DI completed a course of treatment, 12/40 patients are still undergoing treatment, and outcomes are unknown for 13/40. Of those who completed treatment, 11/15 (73%) reported total remission for at least 9months after discontinuing treatment (range 9months-2·5years). Recurrence of symptoms occurred in 4/15 (27%) within 4months of stopping treatment. CONCLUSIONS: Pharmacological treatment of DI can be effective, particularly in a combined dermatology/psychiatry clinic. Most treated patients have a good prognosis, and a remission period can be expected. However, more than 25% of patients may relapse on stopping treatment, with the greatest risk being within the first few months of discontinuation. These patients may require longer treatment courses, or long-term maintenance therapy for symptom control, although further studies are needed to provide recommended guidelines on drug and dosing regimen.

Delusional infestation, including delusions of parasitosis: results of histologic examination of skin biopsy and patient-provided skin specimens.

OBJECTIVE: To review the results of skin biopsies and patient-provided specimens from patients whose assessment was consistent with delusional infestation, including delusions of parasitosis. DESIGN: Retrospective medical record review. SETTING: Mayo Clinic, Rochester, Minnesota. PATIENTS: The study population comprised all patients who were seen at Mayo Clinic and had a diagnosis of delusional skin infestation, including delusions of parasitosis, between 2001 and 2007, and who underwent biopsies as part of their dermatologic evaluations or brought samples to their clinical consultations. MAIN OUTCOME MEASURES: The results of examination of these biopsy and patient-provided specimens. RESULTS: A total of 108 patients met inclusion criteria for this study: 80 received biopsies, 80 had self-procured skin specimens, and 52 patients received biopsies and provided specimens. No biopsy specimen (0 of 80) provided evidence to support skin infestation. The most common interpretations in the 80 biopsy specimens were dermatitis in 49 of 80 (61%); excoriation, ulceration, or erosion in 38 (48%); and nonspecific dermal inflammation in 25 (31%). Patient-provided specimens were most frequently assessed by the physician (generally a dermatologist) evaluating the patient, although 20 of the 80 samples (25%) were submitted for pathologic evaluation. Of these 80 specimens, 10 (13%) contained insects. All but 1 of the insects were noninfesting varieties; 1 (1%) was a pubic louse. The remaining findings consisted of cutaneous debris, environmental detritus, or plant material. CONCLUSION: In patients with suspected delusional infestation, neither skin biopsies nor examination of patient-provided specimens provided objective evidence of skin infestation.

Morgellons disease and delusions of parasitosis.

Morgellons disease is a controversial and poorly defined symptom cluster of skin lesions and somatic symptoms, most notably 'fibers' in the skin. Because of widespread coverage in the media and on the Internet, there are an increasing number of patients presenting to dermatologists. We present three patients who believed that they had fibers in their skin. We offer a discussion of delusions of parasitosis to demonstrate similarities between these conditions. It has been suggested by a limited number of healthcare providers that an unknown infectious agent underlies this symptom complex yet no available evidence supports this assertion. Laboratory values that would be reflective of an infectious process (e.g. elevated white blood cells, sedimentation rate, C reactive protein) are routinely normal and biopsies often reflect only nonspecific findings such as acute and chronic inflammation with erosion or ulceration. Patients with Morgellons disease generally lack insight into their disease and reject the need for psychiatric help. The goal is to build trust and refrain from minimizing what the patient experiences. Attentive examination of the patient's skin and fragments they present is necessary to rule out a true underlying pathologic process and to establish a trusting relationship. A supportive, non-confrontational approach is ideal. The patient is best treated by a team of practitioners of several specialties, including dermatologists, psychiatrists, and counselors.

Gabapentin-induced delusions of parasitosis.

Delusions of parasitosis are a rare psychiatric disorder in which the patient has a fixed, false belief of being infested with parasites. The disorder is classified as primary if no cause is identified or secondary if associated with general organic conditions, psychiatric illnesses, and drugs (substance induced). Several medications have been reported in association with delusions of parasitosis, including anti-parkinsonian medications, ciprofloxacin, cetirizine, doxepin, and others. Delusions of parasitosis have not been previously reported to be associated with gabapentin use. We present the case of a patient who developed delusions of parasitosis after been initiated on gabapentin treatment for neuropathic pain and complete disappearance of symptoms after the medication was discontinued.

Delusional infestation in dermatology in the UK: prevalence, treatment strategies, and feasibility of a randomized controlled trial.

BACKGROUND: Delusional infestation (DI) is considered rare, but true epidemiological studies are only available for Germany. Patients usually contact dermatologists, and psychiatric referral is often impossible. AIM: To estimate the prevalence of DI in UK dermatology clinics, to examine the feasibility of a multicentre randomized controlled trial (RCT) in dermatology, and to evaluate the psychopharmacotherapy of DI in dermatology. METHODS: A short questionnaire survey was distributed to 231 UK dermatologists, asking how many new and ongoing patients with DI they had seen in the past 3 years, which treatments they had used, and whether they thought an RCT would be feasible. RESULTS: The return rate was good (44.6%, n=103 of 231). In total, 103 British dermatology consultants reported 182 cases seen over the past 3 years and 54 current cases. The 3-year prevalence of DI in dermatology outpatients was 4.99 per million; the point prevalence was 1.48 per million. Around a third (35%) of patients were prescribed psychotropic medication, mostly pimozide. Respondents were evenly split in their view of the feasibility of organizing an RCT of treatment of DI. CONCLUSIONS: Our survey covers more than half of the UK population, allowing the first estimate of basic epidemiological data on DI in dermatology in the UK. Our prevalence estimates indicate that DI is not as rare an illness in dermatological practice as previously assumed. There are potential difficulties in organizing an RCT of DI treatment. British dermatologists do not regularly use second-generation antipsychotics as their first choice of treatment.

Morgellons in dermatology.

Delusional parasitosis (DP) is the most frequent delusional disorder in dermatology. In DP there is a fixed belief of a usually skin-related invasion or infestation by a number of alleged infectious species (usually parasites and bacteria), whose identity has varied over the decades. Since 2002 worldwide an increasing number of patients have complained of unverifiable fibers and filaments in or on the skin, associated with numerous nonspecific complaints (arthralgias, altered cognitive function and extreme fatigue). This entity has been named "Morgellons disease" by the patients themselves, although medical evidence for its existence is lacking. As an example, we discuss a 55-year-old woman who complained of Morgellons disease and was treated as if she had DP. Currently the delusional assumption of infestation with Morgellons should be considered as a new type of DP with some kind of inanimate material. We therefore recommend in case of DP including Morgellons the use of the broader term "delusional infestation".