Delusional infestation

State-of-the-Art Review: Evaluation and Management of Delusional Infestation

Delusional infestation is a condition encountered frequently by healthcare professionals across a variety of specialties in which patients have a fixed, false belief that they are infested with living creatures, such as bugs, parasites, worms, or mites, or nonliving objects, such as fibers. Delusional infestation can be debilitating for patients, who not only present with intense psychological distress and physical discomfort but are also at risk of developing numerous dermatological and psychiatric complications. This condition poses unique diagnostic challenges, as these symptoms can occur secondary to many metabolic or infectious causes, as well as unique treatment challenges, with patients frequently refusing psychiatric care and consequently seeking evaluation by other healthcare professionals. In this review, we aim to use existing literature to provide clinicians in infectious diseases or other specialties with sufficient clinical context and treatment guidance for the appropriate management of delusional infestation.

Review of literature and clinical practice experience for the therapeutic management of Morgellons disease

Morgellons disease (MD) is a rare and contentious health condition characterized by dermatological symptoms including slow-healing skin lesions 'attributed' to fibres emerging from or under the skin. Patients also report sensations of crawling, biting and infestation with inanimate objects. This review examines the aetiology, patient characteristics, epidemiology, historical context, correlation with Lyme disease, role of internet, impact on quality of life and treatment approaches for MD. Despite ongoing debate, MD is not officially recognized in medical classifications, with differing views on its aetiology. Some link MD to Lyme disease, while others view it as a variant of delusional infestation. The literature suggests both psychiatric and environmental factors may contribute. The manuscript explores the association with substance abuse, psychiatric comorbidities, infectious agents and the role of internet communities in shaping perceptions. MD's impact on quality of life is significant, yet often overlooked. Treatment approaches are varied due to limited evidence, with low-dose antipsychotics being considered effective, but patient beliefs may influence adherence. A patient-centred, multidisciplinary approach is emphasized, considering both the physical and psychological dimensions of MD. Addressing the controversies surrounding MD while focusing on patient well-being remains a critical challenge for healthcare professionals.

Morgellons disease: a narrative review

Morgellons disease is characterized by the persistent delusion of skin infestation, ultimately inflicting wounds and impairing quality of life. There is insufficient and conflicting research pertaining to this condition, imposing challenges on clinicians in understanding, diagnosing, and treating it. In this review, we summarize the available literature on Morgellons disease including its historical evolution, epidemiology, proposed pathophysiology, underlying structural and functional brain pathologies, typical and atypical clinical presentations, diagnosis, and treatment. A comprehensive review of the literature was conducted on PubMed, Embase, and Scopus using specified keywords. Selected articles were screened by two independent reviewers based on set inclusion and exclusion criteria. Conflicts were resolved by a third reviewer as needed. No limit to the date of selected articles was set due to the scarce literature available on the subject. Morgellons disease is an underdiagnosed entity, owing mostly to the lack of an established pathophysiology and treatment guidelines. While many authors classify it as a type of delusional infestation (DI), others correlate MD with an underlying spirochetal infection, namely Lyme disease. Neuroimaging studies have revealed abnormalities in the "fronto-striato-thalamo-parietal network", a finding common to patients with DI, in addition to alterations in structures related to the "Itch Processing Pathway". Patients tend to extract fibers from their skin lesions and place them in a match box hence the term "match box sign". The diagnosis is that of exclusion, requiring extensive work up to rule out secondary causes and differential diagnoses. Treatment is largely based on the use of antipsychotics, with or without cognitive behavioral therapy. Despite being a diagnosis of exclusion, clinicians must be aware of this entity and have a profound understanding of the pathogenesis underlying it. Upon clinical suspicion, secondary Morgellons should always be ruled out through a thorough history taking, physical examination, and laboratory exams. Despite the challenges brought by the heterogeneous presentation of the condition and the paucity of research revolving around it, the great impact that Morgellons disease has on patients' quality of life forms a pressing need for its adequate detection, diagnosis, and treatment.

Skin Deep: An Overlap of Delusions

Delusional infestation (DI) describes a fixed, false belief where a person believes that they are infested with living or inanimate pathogens despite the absence of medical evidence for such infestation. Descriptions of alleged pathogens have evolved over time, incorporating inanimate objects such as fibrous strands. With the emergence of Morgellons disease and its controversy, we report a case of a 40-year-old female presenting with a strong belief of scabies infestation along with fibers emerging from her skin. Further, although insects are still the most alleged source of infestation, the overlap of Morgellons disease and the delusion of infestation supports it as a DI variant and questions the notion of its existence as a separate diagnostic entity.

Acne excoriée: Diagnostic overview and management

Acne excoriée (AE) is a skin picking disorder (SPD) within the group of obsessive compulsive (OCD) and related disorders characterized by the compulsive manipulation of acne lesions. AE typically appears in females during adolescence or young adulthood and can cause significant disfigurement and psychosocial impairment. This disorder is under-recognized due to patient discomfort to disclose excoriation habits or lack of behavior awareness. It is imperative that dermatologists accurately diagnose and treat this disorder to minimize long-term damage to the skin. This review aims to provide an overview of the diagnosis and treatment options for AE.

Classification of psychodermatological disorders: Proposal of a new international classification

INTRODUCTION

Several classifications of psychodermatology disorders have been proposed, with most of them based on two to four main disorder category groups. However, there is, to date, no classification that has resulted from a consensus established by psychodermatology experts. The DSM-5-TR (Diagnostic and statistical manual of mental disorders (5th ed.), Text Revision) and the ICD-11 (International classification of diseases (11th revision)) also do not provide a systematized approach of psychodermatology disorders. Taking into consideration that classifications are a key pillar for a comprehensive approach to the pathologies of each branch of medicine, the proposal of a classification in psychodermatology appeared as a central need for the recognition of psychodermatological disorders, in an attempt to improve their recognition and, in that sense, to find a common language for the development of this subspecialty that crosses dermatology and psychiatry.

METHODS

Previously published classifications in psychodermatology were critically reviewed and discussed by expert opinion from an international multidisciplinary panel of 16 experts in psychodermatology and a new classification system is proposed, considering classical concepts in general dermatology and psychopathology.

RESULTS

Two main categories of disorders are presented (a main group related to primary mental health disorders and another main group related to primary skin disorders), which are subsequently subdivided into subgroups considering pathophysiological and phenomenological similarities, including key aspects of dermatological examination, namely the presence of visible skin lesions (primary and secondary skin lesions) and psychopathological correlates.

CONCLUSION

This new classification aims to unify previous classifications, systematize the disorders that belong to psychodermatology and highlight their tenuous boundaries, to improve their management. It has been built and approved by the Psychodermatology Task Force of the European Academy of Dermatology and Venereology (EADV), the European Society for Dermatology and Psychiatry (ESDaP) and the Association for Psychoneurocutaneous Medicine of North America (APMNA).

Insights into the Medical Evaluation of Ekbom Syndrome: An Overview

Ekbom syndrome, also known as delusional parasitosis (DP) or delusional infestation, is an uncommon psychiatric disorder distinguished by an enduring conviction of parasitic infestation, persisting notwithstanding the presence of medical evidence to the contrary. Primarily affecting middle-aged women, DP can manifest either as isolated psychological distress or as a component within a more intricate psychiatric framework, substantially influencing the quality of life for affected individuals. Its pathophysiological mechanism involves uncertain dopaminergic imbalances and dysfunction in the dopamine transporter system. Dermatologists often play a pivotal role in diagnosis, as patients first seek dermatological assessments of their signs and symptoms. However, DP frequently originates from underlying psychiatric disorders or medical variables, manifesting with neurological and infectious causative factors. The diagnostic complexity is attributed to patients' resolute convictions, leading to delayed psychiatric intervention. First-line DP treatment involves antipsychotics, with newer agents demonstrating promising prospects, but the lack of standardized protocols poses a significant therapeutic challenge. In this narrative review, both a comprehensive approach to this uncommon pathology and an update on the state of knowledge in this medical subfield focused on optimizing the management of DP are provided. The complexity of DP underlying its uncommon nature and the incomplete understanding of its pathophysiology highlight the need for further research through multicenter studies and multidisciplinary teams to enhance therapeutic efficacy and safety.

Delusional Infestation in Parkinson's Disease Secondary to Piribedil Escalation: An Uncommon Case Report

Delusional infestation (DI) is characterized by delusions of being infested by small microorganisms or even inanimate objects without any medical or microbiological evidence. The pathophysiology of DI is not well understood, and there are two types of DI: the primary form, where there is no underlying cause, and the secondary form, which is related to an associated psychiatric disorder, medical condition, or substance use. DI in Parkinson's disease (PD) is rarely reported, and most published cases are due to antiparkinsonian drugs. Piribedil is a dopaminergic agonist used for the symptomatic treatment of PD either as monotherapy or as adjuvant therapy with other antiparkinsonian treatments. We report the case of an 81-year-old man followed for PD at our institution who developed DI after piribedil dose escalation. When DI is secondary to an antiparkinsonian drug, the treatment of choice is based on withdrawing the implicated drug.

Delusional infestation: a retrospective cohort study of 49 patients over a 6-year period

Delusional infestation (DI) is the fixed false belief of pathogenic infestation of the skin or body despite no supporting medical evidence. It is a relatively rare condition with a reported prevalence of 1.48 per million people. Successful treatment can be challenging as patients are often reluctant to accept referral or involvement of psychiatric services. We report a retrospective cohort study of 49 consecutive patients with a diagnosis of DI, assessed in a regional psychodermatology service over a 6-year period. Low-dose antipsychotics (risperidone or olanzapine) were prescribed in 44 patients. We use our data to explore possible reasons why DI can be challenging to treat. Response to treatment and engagement with services is multifactorial. Our study emphasizes the importance of early assessment and supports the expansion of psychodermatology services in the UK.

The Diagnostic Workup, Screening, and Treatment Approaches for Patients with Delusional Infestation

Delusional infestation (DI) is a psychiatric disorder defined by the fixed, false belief that one has been infested by an organism without evidence to support this. Patients may present with skin lesions and report abnormal cutaneous sensations. The diagnostic workup for patients presenting with delusional infestation is essential to ensuring accurate diagnosis in ruling out other explanations for symptoms and investigating potential secondary causes of DI. In addition to a comprehensive history and physical examination, laboratory workup should be considered depending on the clinical picture. Antipsychotic medications are the most common drugs used in management of adults with DI and tailor the choice of treatment according to patient characteristics. This article serves as a guide for dermatologists, psychiatrists, and other clinicians as it reviews the workup and screening that should be considered when managing a patient with delusional infestation and subsequent treatment protocols once the diagnosis has been made.

White paper on psychodermatology in Europe: A position paper from the EADV Psychodermatology Task Force and the European Society for Dermatology and Psychiatry (ESDaP)

Psychodermatology is a subspecialty of dermatology that is of increasing interest to dermatologists and patients. The case for the provision of at least regional psychodermatology services across Europe is robust. Psychodermatology services have been shown to have better, quicker and more cost-efficient clinical outcomes for patients with psychodermatological conditions. Despite this, psychodermatology services are not uniformly available across Europe. In fact many countries have yet to establish dedicated psychodermatology services. In other countries psychodermatology services are in development. Even in countries where psychodermatolgy units have been established, the services are not available across the whole country. This is especially true for the provision of paediatric psychodermatology services. Also whilst most states across Europe are keen to develop psychodermatology services, the rate at which this development is being implemented is very slow. Our paper maps the current provision of psychodermatology services across Europe and indicates that there is still very much more work to be done in order to develop the comprehensive psychodermatology services across Europe, which are so crucial for our patients.

A Longitudinal Perspective Case Study of Delusional Parasitosis in a Geriatric Psychiatry Unit

Delusional parasitosis is not a common presentation in hospital-based geriatric units. Our aim was to review the presentation of a sudden onset of parasitosis in an older patient who had no prior psychiatric history, and its management. This case report describes an 82-year-old man who presented with delusions of parasitosis for the past three years of his life. The report includes a longitudinal description of the patient's symptoms, signs, and manifestations during his stay at an inpatient senior mental health service center, emergency department (ED) visits, and medical floor stay along with medication management of his psychiatric symptoms with concomitant medical issues. Presentation of delusional parasitosis poses a special challenge not only psychiatrically but also medically and dermatologically. The unique difficulty of finding appropriate antipsychotics for not only the symptoms of parasitosis but also the compulsive behavior that follows a deeply ingrained belief of being infested must be carefully managed, especially in the elderly. Somatic delusions that resemble a plausible but inaccurate reality of infestations could delay treatment as well.

Emerging parasites and vectors in a rapidly changing world: from ecology to management

Global changes have influenced our societies in several ways with both positive (e.g., technology, transportation, and food security), and negative impacts (e.g., mental health problems, spread of diseases, and pandemics). Overall, these changes have affected the distribution patterns of parasites and arthropod vectors with the introduction and spreading of alien species in new geographical areas, eventually posing new challenges in public health. In this framework, the Acta Tropica Special Issue "Emerging parasites and vectors in a rapidly changing world: from ecology to management" provides a focus on the biology, ecology and management of emerging parasites and vectors of human and veterinary importance. Herein we review and discuss novel studies dealing with interactions of parasites and vectors with animals in changing environmental settings. In our opinion, a special focus on the implementation of management strategies of parasitic diseases to face anthropogenic environmental changes still represent a priority for public health. In the final section, key research challenges in this rapidly changing scenario are outlined.

Delusional Parasitosis or Morgellons Disease: A Case of an Overlap Syndrome

Background. Delusional parasitosis (DP) is a monosymptomatic hypochondriacal psychosis where the patient has the delusion of being infested with parasites, whereas Morgellons disease (MD) is described when the patient has fixed ideation of fibers or other materials emerging from skin. Both psychological and organic causes can result into the delusion of infestation, and careful examination is required to exclude secondary causes. Oral DP can result in self-inflected mutilations of the oral mucosa. To our knowledge, oral DP is only rarely reported in the literature. Here, we describe and discuss the management of a case of overlap between oral DP and oral MD at the oral medicine (OM) clinic. Case Report. A 50-year-old male presented to the OM clinic with ulcerations of oral and perioral tissues. Patient reported inflicting wounds to himself using a shaving blade to extirpate worms and pieces of glass from underneath his oral and perioral mucosa. Clinical and laboratory investigations ruled out parasitic infestations. Self-inflected ulcers were treated with topical steroids and prophylactic antifungals, and the patient was referred for psychiatric evaluation. A diagnosis of primary DP was reached, and the patient was managed with antipsychotics. Practical Implications. Oral health care providers should be familiar with oral manifestations of psychiatric disorders and should be able to manage such patients in a multidisciplinary team of internist, dermatologist, and psychiatrist.

Delusional parasitosis: an entomological perspective after a 20-years-experience in two public medical and veterinary entomology laboratories

Delusional parasitosis (DP) is psychiatric disorder characterized by the unshakeable belief of being infested by endo- or ectoparasites, without any evidence of infestations. Hence, DP sufferers often consult medical entomologists or dermatologists, rather than seeking help from a mental health practitioner. Here we present 39 cases of suspected DP occurred in twenty years in two Italian public medical entomology laboratories, to highlight their common features and peculiarities, based on the interviews and material brought to our laboratories. Our results confirmed that DP affects both sexes, but is more frequent in females over the age of 50 years. Cases of psychological contagion, mostly affecting elderly people, were reported within seven family units. Some rare or unique features of DP sufferers involved: the fixed belief to be infested by endoparasites, olfactory hallucinations of unpleasant smell, self-harm to get rid of the imaginary parasite and suicidal thoughts. We suggest the term "Digital pics sign" to describe a modern derivative of the "Matchbox sign", where the DP sufferers showed pictures and videos, in person or sent by email, as proofs of being infested. Medical entomologists, being the most frequently contacted professionals by DP sufferers, may be crucial to raise awareness about this psychological disorder and to encourage a multidisciplinary approach amongst medical professionals and pest control operators.

Treatments for Primary Delusional Infestation: Systematic Review

BACKGROUND

Delusional infestation, also known as Ekbom syndrome, is a rare delusional disorder characterized by the fixed belief that one is infested with parasites, worms, insects, or other organisms. Although delusional infestation is a psychiatric condition, patients often consult dermatologists with skin findings, and it is currently unclear what treatments are recommended for this disorder.

OBJECTIVE

We aimed to systematically review and describe the treatment and management of patients presenting with primary delusional infestation.

METHODS

A systematic search was conducted using Ovid on MEDLINE, Embase, PsycINFO, and the Cochrane Register of Clinical Trials. Relevant data, including treatment, dosage, response, adherence, and side effects, were extracted and analyzed.

RESULTS

A total of 15 case series were included, comprising 280 patients (mean age 53.3 years, 65.4% female) with delusional infestation. Overall, aripiprazole had the highest complete remission rate at 79% (11/14), although this was limited to 14 patients. Among drug classes, selective serotonin reuptake inhibitors were the most effective with a 79% (11/14) complete remission rate and 43% (9/21) partial remission rate in patients with comorbid depression, anxiety, or trichotillomania. First-generation antipsychotics and second-generation antipsychotics had similar complete remission rates (56/103, 54.4% vs 56/117, 47.9%, respectively) and partial remission rates (36/103, 35% vs 41/117, 35%, respectively).

CONCLUSIONS

Due to the rarity of delusional infestation, we only found 15 case series. However, we found that first-generation antipsychotics appear to be similar in effectiveness to second-generation antipsychotics for the treatment of primary delusional infestation. Larger studies and randomized controlled trials are needed to evaluate the efficacy of pharmacological therapy for delusional infestation.

TRIAL REGISTRATION

PROSPERO CRD42020198161; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=198161.

Drug-induced Delusional Infestation

It is considered that certain drugs might induce delusional infestation, yet, to date, no studies have been performed to identify the pharmacodynamics associated with these treatments. The aim of this review is to summarize current available knowledge of drug-induced delusional infestation. A literature search was performed for primary studies on suspected drugs reported to induce delusional infestation. Included articles were evaluated systematically using the Naranjo criteria. In addition, drug mechanisms of action were compared. The final selection included 31 studies, in which a total of 26 classes of drugs were identified. Anti-Parkinson drugs were most frequently associated with delusional infestation, followed by antidepressants, antiepileptics, antibiotics, prescription stimulants, and a few other drug groups. The current available literature suggests that the onset of delusional infestation is initiated by drug-induced alterations in neurotransmitter levels, predominantly dopamine, in the central nervous system.

Delusional Parasitosis in a School Teacher Living in a Rural Area: Parasitological Approach

Delusional parasitosis is a psychotic illness. Patients often present to dermatologists with scars that are self-inflicted because they attempt to extract the “parasites”. We report a 58 -year-old female with an eight-month history of a crawling sensation on her skin and constant generalized itching, which she believed to be caused by insects and worms crawling across her skin. Examination revealed self-inflicted scratches at various stages of healing, which were limited to body parts within easy reach. The patient visited many physicians; it seems that she mutilated in an attempt to remove the offending organisms. She also presented skin scrapings and debris to her doctors, claiming that they contained worms and insects. Light pressure on the lesions did not produce any extrusion of macroparasites, and no parasites such as helminths and insect larvae (myiasis), were observed during microscopy. Thin smear scrapings were stained and examined to rule out parasitic diseases such as leishmaniasis and mycosis; however, no evidence of parasites was found. Our patient was administered with amisulpride 100 mg twice a day, which resulted in the complete remission of delusions after five weeks. The skin lesions were managed with clobetasol propionate ointment. A careful clinical examination combined with parasitological tests can be decisive in diagnosing delusional parasitosis, especially for patients from rural areas. 

Adverse psychocutaneous effects of prescription stimulant use and abuse: A systematic review

Although rare, psychocutaneous disorders induced by prescription stimulants have been reported throughout the literature. A systematic review was conducted to identify all case reports and case series of prescription stimulant-induced trichotillomania, tactile hallucinations, and delusional infestation. A total of 22 case reports were identified and relevant information was analyzed. Patients presenting with trichotillomania and tactile hallucinations induced by prescription stimulants were typically pediatric male patients being treated for attention deficit hypersensitivity disorder. Symptoms resolved after discontinuation of the offending medication. Patients presenting with delusional infestation secondary to stimulant use or abuse were typically adults who were misusing or abusing stimulant medication. Although symptoms typically improved or resolved after decreasing or discontinuing medication, several patients required the use of antipsychotic medication. While the observational nature of case reports and small number of patients limits meaningful analysis of trends and comparison, this study demonstrates that physicians, especially dermatologists and psychiatrists, should be aware of the potential for prescription stimulants to precipitate adverse psychocutaneous disorders in a minority of individuals.

A review of the diagnosis and management of pediatric psychodermatologic conditions: Part II

Pediatric psychodermatologic conditions encompass both primary dermatologic conditions with psychiatric comorbidities and primary psychiatric conditions with self-induced dermatologic manifestations. Detection, diagnosis, and management of primary psychiatric conditions with dermatologic manifestations are challenging due to patient-perceived stigma and lack of educational opportunities for dermatology providers. This two-part series highlights the most up-to-date evidence-based data and management techniques of some of the more common dermatoses of primary psychiatric conditions in children. Part I includes trichotillomania, skin picking disorder, and onychophagia, and part II covers dermatitis artefacta, body dysmorphic disorder, and delusions of parasitosis by proxy, with special considerations for family dynamics.

Case report: Delusional infestation in dementia with Lewy bodies

BACKGROUND

Delusional infestation is characterized by delusions of being infested with parasites, vermin, or small insects and is frequently accompanied by tactile and visual hallucinations. Herein, we report two cases of dementia with Lewy bodies (DLB) with delusional infestation.

CASE PRESENTATION

Case 1 was an 83-year-old man. At the age of 75, he began to show symptoms of rapid eye movement sleep behavior disorder. At the age of 83, he began to complain of visual hallucinations of people and delusional infestation with tactile and visual hallucinations of insects, resulting in the use of insecticides for non-existent insects. He also complained of mild amnesia and was admitted to our psychiatric ward for evaluation and treatment. After admission, the delusional infestation disappeared without any new medication. Based on our examinations, he was diagnosed with probable DLB with delusional infestation. He was treated with 5 mg/day of donepezil hydrochloride; his visual and tactile hallucinations disappeared, and the delusional infestation had not recurred at the 1-year follow-up. Case 2 was a 69-year-old woman. At the age of 60, she underwent clipping for subarachnoid hemorrhage (SAH). At the age of 65, she began to have visual hallucinations of people. At the age of 67, she began to complain of visual illusions in which she mistook lint for insects. At the age of 69, she developed delusional infestation and mild amnesia. She took various actions to get rid of these non-existent insects, including insecticide use, consulting an exterminator, and visiting several dermatologists. She eventually burnt her leg in an attempt to kill the non-existent insects. Based on our examinations, she was diagnosed with prodromal DLB in addition to SAH sequelae. We determined that her delusional infestation was caused by DLB rather than SAH sequelae based on the course of her symptoms. She was treated with a combination of 3 mg/day of donepezil hydrochloride and 12.5 mg/day of quetiapine. Thereafter, the delusional infestation partially improved, and she took no further action against non-existent insects.

CONCLUSION

Delusional infestation may be caused by DLB. Acetylcholinesterase inhibitors (AChEI) may be effective for delusional infestation in DLB, although antipsychotics may also be needed in severe cases.

Right frontal meningioma presenting as delusional parasitosis

Central nervous system tumours can occasionally present with psychiatric symptoms as the only manifestation and can often pose diagnostic challenges. A man in his early 60s presented to the psychiatry outpatient department with delusional parasitosis. His old age and an episode of urinary and faecal incontinence made the clinician consider neuroimaging at the very first visit itself. He was detected to have a right frontal meningioma with features of intracranial hypertension with midline shift, and he underwent emergency surgery. His delusional symptoms completely resolved after surgery and did not recur during the follow-up period of 2.5 years. A right frontal meningioma presenting as delusional parasitosis has probably not been reported in the literature before, and the case is being reported to highlight the rarity of its presentation, the importance of eliciting a detailed clinical history and the need for early neuroimaging in these cases.

Functional neurological disorder and somatic symptom disorder in Parkinson's disease

The occurrence of Functional Neurological Disorder (FND) and Somatic Symptom Disorder (SSD) in PD was not commonly accepted until recently, despite some evidence that emerged in the pre and early L-Dopa era. More recently, the recognition of FND and SSD were noted to be relevant for the management of PD. FND and SSD appear early in the course of PD, often preceding motor symptoms, may interfere with treatment outcomes, often acquire psychotic features during progression, and are mixed with and often concealed by the progressive cognitive decline. We review the related features from the range of the available reports and discuss theoretical models conceived to explain the potential pathophysiological background of these disorders. Finally, we suggest that FND and SSD should be included among the non-motor symptoms of PD and be considered a prodromal feature in a subset of patients. This article is part of the Special Issue "Parkinsonism across the spectrum of movement disorders and beyond" edited by Joseph Jankovic, Daniel D. Truong and Matteo Bologna.

Delusional infestation: an interface with psychiatry

Delusional infestation (delusional parasitosis) is a relatively rare condition but it has been of interest to a wide range of professionals, including entomologists, zoologists and dermatologists, as patients predominantly seek help from specialties other than psychiatrists. The illness requires a multidisciplinary approach and a strong bond of trust between the treating clinician and the patient to ensure the best possible outcome. This article discusses how clinicians in all specialties should approach patients presenting with the disorder and outlines differential diagnosis and associated laboratory tests. It considers the evidence base for treatment and the success of psychodermatology clinics that provide a ‘neutral setting’ for consultation to address the problem of patients’ non-engagement. Such clinics are few, and there is a need to develop disease-specific pathways in primary care and hospital settings to improve prognosis.

Delusional infestation in clinical practice over a period of two decades

Introduction

Patients presenting with cutaneous symptomatology may in fact suffer from underlying psychiatric conditions. Individuals diagnosed with delusional infestation (DI) have a fixed false belief of being infested with certain organisms or objects.

Aim

To analyse clinical features of subjects with DI who were admitted to the tertiary dermatology ward.

Material and methods

A retrospective analysis concerning DI patients hospitalized between 1997 and 2019 was carried out. The emphasis was put on the duration of symptoms, psychiatric symptomatology (including the "specimen sign"), comorbidities as well as therapy.

Results

We gathered data regarding 21 consecutive patients with DI. The mean age of subjects was 65.2 ±13.3 years, the majority were females (76.2%). The mean time span between the disease onset and diagnosis was 1.9 ±1.7 years. Previous psychiatric consultations were attended by 57.0% of patients. The specimen sign was present in 47.6% of cases, whereas the most common suspected causative factors were described as worms (52.4%), unspecified parasites (42.9%), "something" (33.3%) and flies (19.0%). Primary delusional disorder was diagnosed in 76.2%, followed by shared delusional disorder and secondary delusional disorder of organic origin (9.5% each). Risperidone monotherapy was initiated in 61.9% of patients. In total, only 33.3% of patients attended the follow-up visit.

Conclusions

DI features a wide spectrum of clinical signs and symptoms. Risperidone remains the drug of choice in the majority of cases. Successful management of each DI case requires collaboration between dermatologists and psychiatrists and still remains a major challenge.

The skin crawls, the stomach turns: ectoparasites and pathogens elicit distinct defensive responses in humans

Disgust has long been viewed as a primary motivator of defensive responses to threats posed by both microscopic pathogens and macroscopic ectoparasites. Although disgust can defend effectively against pathogens encountered through ingestion or incidental contact, it offers limited protection against ectoparasites, which actively pursue a host and attach to its surface. Humans might, therefore, possess a distinct ectoparasite defence system-including cutaneous sensory mechanisms and grooming behaviours-functionally suited to guard the body's surface. In two US studies and one in China, participants (N = 1079) viewed a range of ectoparasite- and pathogen-relevant video stimuli and reported their feelings, physiological sensations, and behavioural motivations. Participants reported more surface-guarding responses towards ectoparasite stimuli than towards pathogen stimuli, and more ingestion/contamination-reduction responses towards pathogen stimuli than towards ectoparasite stimuli. Like other species, humans appear to possess evolved psychobehavioural ectoparasite defence mechanisms that are distinct from pathogen defence mechanisms.

Cogito, ergo praedico (I think, therefore I predict)

I comment on a new overview of the treatment of delusional infestation. I focus on the challenges of communicating with a patient who has delusions and evaluate practical advice. I look at philosophical models to explain those communication problems as well as theories of delusional formation, and examine how these may help clinicians to understand and overcome those challenges.

Aberrant Gray Matter Volume and Cortical Surface in Paranoid-Type Delusional Disorder

INTRODUCTION

Delusions are core symptoms of schizophrenia-spectrum and related disorders. Despite their clinical relevance, the neural correlates underlying such phenomena are unclear. Recent research suggests that specific delusional content may be associated with distinct neural substrates.

OBJECTIVE

Here, we used structural magnetic resonance imaging to investigate multiple parameters of brain morphology in patients presenting with paranoid type delusional disorder (pt-DD, n = 14) compared to those of healthy controls (HC, n = 25).

METHODS

Voxel- and surface-based morphometry for structural data was used to investigate gray matter volume (GMV), cortical thickness (CT) and gyrification.

RESULTS

Compared to HC, patients with pt-DD showed reduced GMV in bilateral amygdala and right inferior frontal gyrus. Higher GMV in patients was found in bilateral orbitofrontal and in left superior frontal cortices. Patients also had lower CT in frontal and temporal regions. Abnormal gyrification in patients was evident in frontal and temporal areas, as well as in bilateral insula.

CONCLUSIONS

The data suggest the presence of aberrant GMV in a right prefrontal region associated with belief evaluation, as well as distinct structural abnormalities in areas that essentially subserve processing of fear, anxiety and threat in patients with pt-DD. It is possible that cortical features of distinct evolutionary and genetic origin, i.e. CT and gyrification, contribute differently to the pathogenesis of pt-DD.

Delusional Infestation Secondary to the Dopamine Agonist Ropirinole in a Patient With Parkinson's Disease: A Case Report With an Outline of the Biology of Psychosis

Delusional infestation (DI) is a thought disorder, a delusion that one is infested with pathogens. Remarkably, these patients do not typically exhibit symptoms of anxiety or depression. The role of the dopamine D2 receptor is central to the idea of psychosis. In this article, we present a case of ropirinole-induced delusional skin infestation in a patient with Parkinson's disease, that was reversible with drug discontinuation. We seize upon this opportunity to discuss the pathology of the dopamine receptors, the glutamate N-methyl D-aspartate (NMDA) receptors and the serotonin 5-hydroxytryptamine (5HT-2A) receptors in the generation of psychosis. We outline the fundamental pharmacodynamical differences between the typical and atypical anti-psychotics that will help us understand how these agents work favorably and adversely. We also briefly review the neuroradialogy of psychosis and adumbrate on the mismatch between the meso-limbic system (motivational) and the salience network (valence) as the driver of the psychotic phenomenon.

Delusional infestation: Clinical presentations, diagnosis, and management

BACKGROUND

Delusional infestation is a primary psychiatric disorder characterized by a somatic-type delusional disorder (primary delusional infestation) that may lead to self-induced cutaneous lesions which are often difficult to recognize and treat properly. It may be also secondary to other psychiatric disorders, medical diseases, or substance abuse.

AIMS

This review will describe prevalence, common clinical features, different clinical presentations, differential diagnoses, and treatment recommendation. Special focus has been put on psychological aspects.

METHODS

We conducted a literature search on PubMed from January 2001 to June 2020 with the search terms of delusional parasitosis, delusional infestation, psychological, Reference lists of identified articles were examined for further relevant studies. The search was limited to English language articles. No specified quality criteria were used for study inclusion.

RESULTS

The clinical manifestations of delusional infestation are very important in the differential diagnosis and its psychological implications and management perspectives.

CONCLUSION

This article presents an update regarding the clinical aspects and treatment options of delusional infestation in order to provide an up-to-date review for dermatologists and general practitioners.

An introduction to the assessment and management of psychodermatological disorders

Psychodermatology is an emerging field at the interface between psychiatry, psychology and dermatology. There is a strong bidirectional relationship between a number of dermatological disorders and psychiatric disorders. This article provides an overview of psychiatric disorders with dermatological symptoms, and dermatological disorders with secondary psychophysiological consequences. The principles of management and our insights into establishing a psychodermatology service in the UK are discussed.

Coexistence of Primary and Secondary Delusional Parasitosis

Objective

Delusional parasitosis (DP) is a difficult-to-treat condition. It is prevalent in all cultures, societies, and countries. Previous case reports of DP have been published; however, the patient presented in this report is unique because of the co-occurrence of both primary and secondary types of DP. We aim to explore the two subtypes of DP.

Conclusions

We discuss DP from a nosological perspective and also highlight the various theories at play in the pathogenesis of primary and secondary DP. The different subtypes of DP should be taken into consideration as they also have a bearing on the management.

Historical and clinical considerations on Ekbom's syndrome

Ekbom's syndrome represents a relatively uncommon neuropsychiatric condition characterized by the recurrent and bizarre fixed delusional belief to be infested by small organisms or even unanimated materials ('Morgellons disease'), without any objective evidence of infestation/parasitosis. The condition, mainly diagnosed in a nonpsychiatric setting, is supposed to be largely underestimated and, hence, undermanaged. The present comprehensive review aims at investigating Ekbom's syndrome, from a historical, epidemiological, clinical and therapeutic perspective, by providing diagnostic-treatment strategies in managing this condition in routine psychiatric clinical settings. The prototypical patient is a middle-aged woman (or a younger subject in those cases in which substance and/or alcohol abuse is implicated), often single, divorced or widowed (loneliness component and social withdrawal), who has already consulted several specialists due to skin lesions associated with a firm and delusional belief to be infested. The identification and diagnosis are challenging due to poor patient's insight, poor knowledge and collaboration between specialists and differential diagnoses to be considered before asking for a psychiatric referral. Management and treatment strategies mainly derive from isolated case reports or observational studies with a small sample size. Further randomized clinical trials should be performed to evaluate the efficacy of newer antipsychotic drugs, including long-acting injectable formulations.

Update on Pharmacotherapy in Psychodermatological Disorders

Psychodermatological (PD) conditions encountered in dermatologic practice include primary psychiatric conditions such as delusions of parasitosis or secondary psychiatric conditions such as anxiety and depression due to dermatologic disease. The psychotropics include antipsychotic agents, anti-anxiety agents, antidepressants, and miscellaneous drugs such as anti convulsants. Anti psychotics are further divided into first-generation and second-generation drugs. Currently, second-generation drugs e.g., risperidone are preferred over first-generation drugs e.g., pimozide in delusional infestation owing to the side effect profile of the latter. Anti-anxiety agents include benzodiazepines used in acute anxiety and buspirone in chronic anxiety disorders. They are frequently prescribed along with antidepressants. Although dependence and necessity of tapering is a problem with benzodiazepines, delayed onset of action is a feature of buspirone. The commonly used antidepressants in dermatology include selective serotonin reuptake inhibitors (citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine, and sertraline), selective serotonin norepinephrine reuptake inhibitors (venlafaxine, desvenlefaxine, and duloxetine), norepinephrine dopamine reuptake inhibitors (bupropion), tricyclic antidepressants (doxepin, amitriptyline, imipramine, and clomipramine), and tetracyclic antidepressants (mirtazapine). Miscellaneous drugs include anticonvulsants such as gabapentin and pregabalin, naltrexone, and N-acetyl cysteine. The principles of PD treatment are first establish the psychiatric diagnosis, followed by initiating drug treatment. The choice of drugs is dependent on multiple factors such as side-effect profile, drug interactions, and co-morbid conditions. Usually, drugs are started at a low dose and gradually increased. A literature search was done in Pubmed, Google Scholar, and Medline databases, and articles on treatment were analyzed.

A systematic review of antipsychotic agents for primary delusional infestation

BACKGROUND

Delusional infestation (DI) is a rare delusional disorder in which individuals have a false belief that they are infested with bugs, parasites, or insects, despite the lack of medical evidence that such an infestation exists. Data on the effectiveness of antipsychotics for DI are limited.

METHODS

We conducted a systematic review using EMBASE, MEDLINE, PsycINFO, and Cochrane Central Register of Controlled Trials from inception of the databases up until July 20, 2018. Studies examining typical or atypical antipsychotics for primary DI were included.

RESULTS

A total of 51 relevant articles were identified, primarily case reports/series. Overall response was favorable for both typical and atypical antipsychotics, but there was no strong evidence to suggest that any one antipsychotic agent was preferable to other agents. Pimozide (1-16 mg/day) and risperidone (0.5-8 mg/day) were the most commonly studied typical and atypical antipsychotics, respectively. Inconsistent reporting of treatment outcomes and variability in study designs limited the overall evaluation of the data.

CONCLUSIONS

There remains a lack of sound data supporting the effectiveness of antipsychotic treatment for primary DI. Further research is required to establish more definitive conclusions about the relative clinical utility of antipsychotic agents for DI.

Classification and Staging of Morgellons Disease: Lessons from Syphilis

INTRODUCTION

Morgellons disease (MD) is a contested dermopathy that is associated with Borrelia spirochetal infection. A simple classification system was previously established to help validate the disease based on clinical features (classes I-IV).

METHODS

Drawing on historical and pathological parallels with syphilis, we formulated a more detailed staging system based on clinical features as well as severity of skin lesions and corresponding histopathological infection patterns, as determined by anti-Borrelia immunohistochemical staining.

RESULTS

Clinical classes I-IV of MD are further categorized as mild, moderate and severe, or stages A, B and C, respectively, based on histopathological findings. Stage A lesions demonstrated little or no immune infiltrates and little or no disorganization of cells; macrophages were not present, and hemorrhage was negligible. Extracellular isolated spirochetes and intracellular staining of keratinocytes in the lower epidermis was occasionally seen. Stage C lesions demonstrated positive staining of keratinocytes in the stratum basale and stratum spinosum and positive intracellular staining of macrophages for Borrelia. Aggregate Borrelia colonies were frequently encountered, hemorrhage was frequent, and intracellularly stained fibroblasts were occasionally seen. Stage B lesions demonstrated a pattern intermediate between Stages A and C.

CONCLUSION

The enhanced staging system provides objective criteria to assess the severity of dermopathy in MD. Further studies are needed to determine the optimal treatment for MD based on this staging system related to Borrelia infection.

Delusional infestation managed in a combined tropical medicine and psychiatry clinic

Background

Delusional infestation (DI) is a well-recognised delusional disorder presenting as the persisting belief in the presence of parasitic or other infestations. Combined clinics have been run by dermatology and psychiatry in a small number of centres. Here we report the first few years of a unique combined clinic run with experts in infectious diseases/tropical medicine and psychiatric management of DI.

Methods

We reviewed all patients seen at the combined assessment clinics run at the Liverpool School of Tropical Medicine between 19 December 2011 and 31 October 2016. Data were collected prospectively as part of clinical assessment. Descriptive analysis of these data was performed to examine clinical features at assessment, investigations performed and treatment outcomes.

Results

A total of 75 patients were assessed and 52 (69%) were given the formal diagnosis of DI. A history of travel was given by 64% of individuals but no significant tropical or infectious diagnosis was made. Of those who returned for follow-up, 61% reported improvement in symptoms. The Clinical Global Impressions Severity scale improvement was 1.36 for DI patients but only 0.63 for non-DI patients. DI patients were more impaired at baseline (5.0 vs 4.1). Health anxiety was the most common diagnosis seen in those not considered to have DI.

Conclusions

Combined clinics to treat DI are effective in improving patient outcome. A significant minority of patients referred do not have a diagnosis of DI.

Abnormal cerebellar volume in somatic vs. non-somatic delusional disorders

Background

There is abundant evidence for cerebellar involvement in schizophrenia, where the cerebellum has been suggested to contribute to cognitive, affective and motor dysfunction. More recently, specific cerebellar regions have also been associated with psychotic symptoms, particularly with auditory verbal hallucinations. In contrast, little is known about cerebellar contributions to delusions, and even less is known about whether cerebellar involvement differs by delusional content.

Methods

Using structural magnetic resonance imaging at 1.0 T together with cerebellum-optimized segmentation techniques, we investigated gray matter volume (GMV) in 14 patients with somatic-type delusional disorder (S-DD), 18 patients with non-somatic delusional disorder (NS-DD) and 18 patients with schizophrenia (SZ) with persistent non-somatic delusions. A total of 32 healthy controls (HC) were included. Between-group comparisons were adjusted for age, gender, chlorpromazine equivalents and illness duration.

Results

Compared to HC, S-DD patients showed decreased GMV in left lobule VIIIa. In addition, S-DD patients showed decreased GMV in lobule V and increased GMV in bilateral lobule VIIa/crus II compared to NS-DD. Patients with SZ showed increased GMV in right lobule VI and VIIa/crus I compared to HC. Significant differences between HC and NS-DD were not found.

Conclusions

The data support the notion of cerebellar dysfunction in psychotic disorders. Distinct cerebellar deficits, predominantly linked to sensorimotor processing, may be detected in delusional disorders presenting with predominantly somatic content.