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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., Competing Interests: Potential conflicts of interest. The authors: No reported conflicts of interest. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

This review synthesized evidence on the most up-to-date treatment outcomes in patients with delusional parasitosis and examined the impact of incorporating psychological interventions in conjunction with psychiatric treatment. The reporting of this review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. PubMed and Google Scholar were searched between 2013 and 2023. Nine studies were included in this review. Partial remission was observed across all cases, irrespective of the treatment approach employed. Complete remission was limited to only three studies. No correlation was observed between the incorporation of psychological intervention in conjunction with psychotropic medication and an enhanced remission outcome. The findings underscore the importance of psychotropic medication as a fundamental component in the treatment of delusional parasitosis. The results highlight that although first- and second-generation psychotropic medications are the mainstay treatment options, they nevertheless play a limited role because of the patients' steadfast delusions of infestations., (© 2023 the International Society of Dermatology.)

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.

Psychodermatological problems are prevalent in dermatology practices. Among those, delusional infestation (DI) is the subject of one of the most challenging patient encounters practicing dermatologists may experience. This difficulty arises, at least partly, from the unavailability of psychiatric knowledge and skillset necessary to properly manage these patients, reflecting that most dermatology residency programs are unable to provide training in psychodermatology. This relates to the lack of faculty available with such expertise. This article reviews various suggestions made in the medical literature to try to improve this current unfortunate situation. However, the more common suggestion regarding organizing a multidisciplinary psychodermatologic clinic may be difficult to achieve as reflected by the scarcity of such clinics in the U.S. The authors offer alternative suggestions beyond the idea of organizing a multidisciplinary clinic.

Introduction: Ekbom syndrome is a rare disease characterized by a delusional conviction on the part of the patient of infestation with cutaneous parasites. It is rarely described in an African setting. Herein we report three cases observed in Ouagadougou., Patients and Methods: Case 1: a 40-year-old housewife, living alone since her spouse left her, consulted for a feeling of insects under the skin and exulceration progressing over the previous year. A diagnosis was made of Ekbom syndrome in a depressed patient. Case 2: a 45-year-old bachelor, unemployed and with no children, consulted in dermatology for a sensation of continuous movement of insects under his skin, experienced over the previous six years. This sensation, which was worse in hair-covered areas, led to regular hair removal and untimely cleansing in a bid to dislodge them. Case 3: an 80-year-old patient, widowed for 3 years, consulted for a sensation of insects under her skin over the previous 2 years. This sensation was accompanied by intermittent pruritus and she removed the "insects" from her skin, which she brought to us in a sachet, but which in reality corresponded to debris of dead skin. We concluded on Ekbom syndrome in a depressive patient., Conclusion: These three cases of delusional parasitism observed in Ouagadougou, Burkina Faso, confirm the main clinical characteristics of Ekbom syndrome and underline the role of emotional and financial isolation, as well as pre-existing psychological difficulties, as potential triggers for this syndrome., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

Delusional parasitosis manifests as a fixed, false belief that an individual is infested by living organisms. Primary delusional parasitosis is a psychiatric disorder with the delusion as an isolated manifestation, whereas secondary delusional parasitosis is a delusion occurring secondary to a psychiatric disorder, substance use, or medical illness. A 62-year-old woman with no psychiatric history presented to the Emergency Department with two to three months of "whole body itching" and seeing small insects crawling on her skin and in her hair. Exam of her skin and scalp was notable for no appreciable lesions, rashes, excoriations, or insects. Her neurologic exam was notable for full visual fields, and no localizing deficits. A non-contrast head CT demonstrated a nonspecific heterogeneous low-attenuation lesion within the medial right occipital lobe, and a follow up MRI confirmed a right posterior cerebral artery distribution subacute infarction. She was admitted for two days, and ultimately was discharged on aspirin and atorvastatin for secondary prevention. An emergency physician should remain vigilant in his/her assessment of patients with seemingly psychiatric symptoms, in particular elderly patients with no known psychiatric illnesses. Neuroimaging should be amongst studies considered in the evaluation of elderly patients presenting with new onset psychiatric complaints., (Copyright © 2019 Elsevier Inc. All rights reserved.)

We report a case of 'delusional parasitosis by proxy'. A sixyear old child was brought to the emergency department by a mother with concerns that her son had a skin and scalp infestation. Despite the absence of any clinical findings being found on exam, the mother remained disproportionately concerned. Follow up care was recommended with the child's primary care. The mother returned to the ED with her child three weeks later with concerns that her son had an inflamed scalp and eyes. The mother remained insistent that the child was infested with bugs and she had sought care at two other locations where the child was prescribed permethrin on both visits. She had been applying the medication repeatedly. On exam the boy's scalp had been shaved and was erythematous and irritated; his eyebrows and eyelashes had also been shaved off and likely contributed to an irritant conjunctivitis from repeated applications of topical permethrin lotion. No evidence of infestation was identified. We recruited the assistance of the maternal grandparents, child protective services and primary care pediatrics and the child was removed from the mother's custody and placed into the custody of the grandparents. Six weeks later with basic skin care and erythromycin ophthalmic ointment for the eyes, the child's hair, eyebrows and eyelashes grew had grown in, and the scalp irritation had resolved. The mother had sought and received psychiatric care and was improving., (Copyright © 2019. Published by Elsevier Inc.)

Trichotillomania is a condition characterized by the pulling of hair from anywhere on the body and is classified as an obsessive-compulsive and related disorder. Patients with hair disorders are commonly referred to psychodermatology services, and can represent a management challenge. Few publications exist that report outcomes for patients with trichotillomania in real clinical practice. We report 12 such patients seen within our own psychodermatology service, who were managed using a variety of treatment strategies. The rate of defaulting of appointments was high, but improvements were seen in patients engaging with services., (© 2019 British Association of Dermatologists.)

Delusional infestation is the conviction that one is infested with pathogens-either animate or inanimate-despite medical or microbiologic evidence to the contrary. Infestation with inanimate pathogens, specifically fibers or filaments, has been controversially termed Morgellons disease by the patients themselves, who believe that this is not a psychiatric disease but rather a new organic condition or a skin manifestation of an infection, such as Lyme disease. A large-scale study by the Centers of Disease Control and Prevention on patients presenting with Morgellons clinical manifestations did not find evidence of fibers in the skin nor an association with any infection, including Lyme disease. Once the diagnosis of delusional infestation is made, the cornerstone of treatment is antipsychotics, although this is often quite challenging, as patients are reluctant to take these medications., (Copyright © 2018 Elsevier Inc. All rights reserved.)

A 57-year-old Caucasian female presented to our clinic with her 23-year-old son, who was profoundly autistic. Our patient was convinced that her son had an infestation with fibers and believed that he had developed the condition as a young child. She described the symptoms of the infestation in her son's skin on his behalf, as he was not able to communicate. She identified dietary factors as a causative factor and wanted them removed from his diet. Her son had seborrhoeic dermatitis on examination, with no evidence of an infestation. Our patient later identified that fibers were coming out of her skin also. Her medical history included a road traffic accident resulting in back pain. Blood, urine, and microbiological investigations were normal. She was diagnosed with delusional infestation (DI) by proxy, and was started on risperidone. We present an interesting case of a patient with DI by proxy, in which the delusional beliefs of the mother have been projected onto her son. Issues of safeguarding vulnerable adults are raised in such cases, suggesting the crucial role of the physician in ensuring patient safety. DI by proxy has been reported in patients with children and animals, but we believe this is the first report of DI by proxy involving a vulnerable adult., (© 2018 Wiley Periodicals, Inc.)

We examined the association between the duration of untreated psychosis and outcome for patients with delusional infestation. This multi-centre international study included 211 consecutive patients. Illness severity was evaluated at first presentation and outcome was measured with the Clinical Global Impression scale (CGI) at baseline and follow-up. A regression analysis showed a clear clinical and statistically significant association between shorter duration of untreated psychosis and better outcome at follow-up. Patients with a duration of untreated psychosis of less than one year showed a CGI-S change from 5.37 to 2.07; those with a duration of untreated psychosis of 1-5 years a change from 5.48 to 2.59, and those with a duration of untreated psychosis of >5 years a change from 5.59 to 3.37. This difference of 1.1 CGI points between the groups resembles a clinically relevant difference in patient outcome. Our results suggest that longer duration of untreated psychosis in patients with delusional infestation is associated with significantly less favour-able clinical outcomes.

Perceptions of the clinical management of delusional infestation (DI) were compared with clinical outcomes in this 10-year case series from a single centre in Dundee, UK. An online questionnaire (survey-monkey, a TM brand of online survey available for free for basic use) was sent to Scottish Dermatologists to gauge their opinions and confidence in the management of DI. Also, a retrospective review of medical case notes of patients seen by dermatologists in one institution was undertaken and clinical outcomes were reported by patients' general practitioners (GP). The survey showed that 61% of responding dermatologists encountered 1-5 cases of DI per year. Twenty-four percent respondees were 'confident' in managing patients with DI, 54% were 'somewhat confident'. Forty-seven patients (62% female, 70% single) were seen over the 10 years; 43% brought a self-collected specimen to clinic, 68% of patients had a psychiatric comorbidity, 23% of patients had primary DI and 11/47 (23%) were seen by a psychiatrist. Clinical outcomes as rated by patients' GPs were reasonable or good in 2/3 patients. A poor outcome was seen in 12 patients and associated with chronic pain in 50% (p < 0.01) and psychiatric comorbidity in 100% (p < 0.01). We conclude that good outcomes can be achieved in some patients with DI without psychiatric input and without psychoactive treatment.

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.

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.

Individuals with obsessive-compulsive features frequently visit dermatologists for complaints of the skin, hair or nails, and often progress towards a chronic relapsing course due to the challenge associated with accurate diagnosis and management of their psychiatric symptoms. The current DSM-5 formally recognizes body dysmorphic disorder, trichotillomania, neurotic excoriation and body focused repetitive behavior disorder as psychodermatological disorders belonging to the category of Obsessive-Compulsive and Related Disorders. However there is evidence that other relevant skin diseases such as delusions of parasitosis, dermatitis artefacta, contamination dermatitis, AIDS phobia, trichotemnomania and even lichen simplex chronicus possess prominent obsessive-compulsive characteristics that do not necessarily fit the full diagnostic criteria of the DSM-5. Therefore, to increase dermatologists' awareness of this unique group of skin disorders with OCD features, we propose a novel classification system called Obsessive-Compulsive Insight Continuum. Under this new classification system, obsessive-compulsive skin manifestations are categorized along a continuum based on degree of insight, from minimal insight with delusional obsessions to good insight with minimal obsessions. Understanding the level of insight is thus an important first step for clinicians who routinely interact with these patients.

Background: Monosymptomatic hypochondriac psychosis (MHP) patients present with a delusional ideation that revolves around one particular hypochondriac concern. Delusional infestation is the most common type of MHP seen by the dermatologist., Objectives: This study was designed to retrospectively investigate a group of patients with delusions of infestation seen in an academic medical center in São Paulo, Brazil., Methods: A retrospective study of patients presenting with delusional infestation between 2007 and 2014 was conducted. Records were reviewed to study personal data, symptoms, and treatments., Results: Thirty patients were studied (22 female, eight male). Their mean age was 58 years in men and 60 years in women. Twenty-four patients spent most of their time at home (i.e. they were housewives, retired, or unemployed). The duration of disease varied from 3 months to 20 years. Fifteen patients brought in fragments of material that they believed to be parasites ("specimen sign"). Treatment consisted of the antipsychotic drugs pimozide (1-6 mg/d) or olanzapine (5-10 mg/d). Three patients did not return for follow-up. Follow-up varying from 2 months to 7 years was recorded in 24 patients. Two patients were treated with other psychoactive drugs prescribed by psychiatrists for additional psychiatric diagnoses. Control of symptoms was achieved in the majority of patients who underwent adequate follow-up., Conclusions: Delusional infestation is an extremely chronic disease. Attempts to discontinue treatment in those patients in whom a lengthy follow-up was performed inevitably resulted in symptom relapses., (© 2015 The International Society of Dermatology.)

The literature on chronic pruritus, paresthesia and delusional infestation indicates that a wide variety of conditions ranging from AIDS to vitamin deficiencies may cause these symptoms. In many, or perhaps most of these cases, activation of itch pathways seems to be the underlying cause of the skin sensations and perhaps even the visual hallucinations characteristic of delusional infestation. The principle difference between diagnoses of chronic pruritus and delusional infestation appears to lie in the patient's interpretation of the cause of the symptoms, rather than underlying physiological differences. Delusional infestation, paresthesia and chronic pruritus must be considered symptoms of underlying conditions.

Acquired perforating disorders are a group of uncommon skin conditions characterized by transepidermal extrusion of altered dermal material, most often associated with diabetes mellitus and chronic kidney failure. Delusional parasitosis is a primary psychiatric disorder in which affected patients have fixed, false beliefs that their skin is infested by parasites, in the absence of any evidence supporting their statements. A 69 year old malepatient addressed the Dermatology Department for a skin eruption consisting of multiple umbilicated keratotic papules with a generalized distribution. The patient believed that the lesions were produced by small parasites entering and exiting his skin. The histopathological examination confirmed the clinical diagnosis of Kyrle's disease. The psychiatric examination established the diagnosis of delusions of parasitosis. This is the first reported case of Kyrle's disease associated with delusions of parasitosis. There is no evidence supporting the hypothesis that delusions of parasitosis might be a predisposing factor for Kyrle's disease. However, we believe that the pruritic dermatosis might have triggered the delusions of parasitosis due to the associated pruritus. On the other hand the constant excoriations and traumatizing of a skin prone to develop idiopathic Kyrle's disease in the attempt to remove the parasites prevented the complete resolution of the lesions.

Introduction: Delusional parasitosis is a rare psychiatric disorder which often presents with dermatological problems. Delusional parasitosis, which involves urethral self-instrumentation and foreign body insertion, is exceptionally rare. This is the first case report to date that provides a detailed presentation of the urological manifestation of delusional parasitosis with complications associated with repeated self-instrumentation and foreign body insertion, resulting in stricture formation and requiring perineal urethrostomy., Case Presentation: A 45-year-old Irish man was electively admitted for perineal urethrostomy with chronic symptoms of dysuria, haematuria, urethral discharge, and intermittent urinary retention. He reported a 4-year history of intermittent pain, pin-prick biting sensations, and burrowing sensations, and held the belief that his urethra was infested with ticks. He also reported a 2-year history of daily self-instrumentation, mainly injecting an antiseptic using a syringe in an attempt to eliminate the ticks. He was found to have urethral strictures secondary to repeated self-instrumentation. A foreign body was found in his urethra and was removed via cystoscopy. On psychiatric assessment, he displayed a fixed delusion of tick infestation and threatened to surgically remove the tick himself if no intervention was performed. The surgery was postponed due his mental state and he was started on risperidone; he was later transferred to an acute in-patient psychiatric unit. Following a 3-week admission, he reported improvement in his thoughts and distress., Conclusions: Delusional parasitosis is a rare psychiatric disorder. Self-inflicted urethral foreign bodies in males are rare and have high comorbidity with psychiatric disorders; hence, these patients have a low threshold for referral for psychiatric assessment. The mainstay treatment for delusional parasitosis is second-generation antipsychotic drugs.

Primary psychiatric disorders where skin changes appear most frequently include: delusions of parasitosis, body dysmorphic disorder, neurotic excoriations, dermatitis artefacta, and trichotillomania. In all these diseases the primary pathologic condition is of psychiatric nature, and the skin changes are secondary and self-induced. In this review we wanted to present the epidemiology, clinical pictures, and treatment options for these disorders. These patients are more frequently seen in dermatology clinics, as they may be unwilling to acknowledge a psychiatric basis for their psychical symptoms. If we want the treatment to be effective and timely, it is important for the dermatologist to understand the underlying psychopathology of these conditions. Treatment should be gradual. An initially supportive, nonconfrontational, empathic approach to the patient is indicated. Immediate confrontation regarding the suspicion that the patient's lesions are self-induced can be counterproductive in that the patient will often refuse treatment. Frequent visits and symptomatic topical treatments are useful in the beginning. The goal is to establish a trusting and supportive enough relationship with the patient so that he or she will accept a psychiatric referral to explore the complex personality and behavioral issues that often underlie these conditions.

The Ekbom syndrome or delusional parasitosis is an uncommon psychiatric condition, in which the main symptom is the delusion of being infested with living organisms such as parasites, bacteria, virus, bugs or worms. The case is presented of a 34 year-old man with symptoms compatible with the syndrome. The available literature is briefly reviewed and theoretical correlation with clinical symptomatology is made. The patient had a primary and mixed Ekbom syndrome., (Copyright © 2014 Asociación Colombiana de Psiquiatría. Publicado por Elsevier España. All rights reserved.)

Physicians are not infrequently consulted by distraught patients with delusions of infestation who believe that they are infested with external or internal parasites and describe a crawling sensation of bugs or worms on or under their skin. Internet search engines were queried with the keywords as search terms to examine the latest articles on delusional infestations in order to describe presenting manifestations, differential diagnoses, and effective management strategies. The demographic and behavioral features of delusional infestations have remained constant and include: (1) onset in well-educated, middle-aged adults who are pet owners; (2) production of purported specimens of causative parasites; (3) pesticide overtreatment of themselves, their households, and pets; (4) excessive cleaning or vacuuming of households; (5) intense anger and resentment directed at physicians failing to confirm their self-diagnoses; and (6) sharing delusional symptoms with spouses or relatives. Although some reports have suggested that cases of delusional infestation are increasing today in the tropics, most studies have confirmed a stable incidence over time and similar disorder demographics worldwide. However, management strategies for delusional infestations have changed significantly over time with second generation, atypical antipsychotics offering safer adverse effect profiles and better prognoses than earlier therapies with first generation, typical antipsychotics. The most effective management strategies for delusional infestations include empathetic history-taking and active listening to the patient, careful exclusion of true parasitoses, and a therapeutic regimen that includes a second generation neuroleptic agent.

Background: Unusual delusional syndromes are rare protean diseases with speculative etiopathogenic mechanisms., Methods: Seven consecutive patients with advanced PD were evaluated over a 15-year period at the Movement Disorders Unit in the Neurology Service, Hospital de Clínicas, Federal University of Paraná, and the Paraná State Parkinson's Patients Association., Results: We describe advanced Parkinson's disease patients presenting with unusual delusional syndromes, including cases of Ekbom, Othello, Capgras' and Diogenes syndromes, reduplicative paramnesia and mirrored-self misidentification., Conclusion: There are a few isolated reports of unusual neuropsychiatric disorders in patients with PD. We believe that these syndromes associated with advanced PD in elderly patients presenting with cognitive impairment and polypharmacy are probably often underestimated. Neurologists should be aware for these rare and treatable conditions., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Patients with delusional infestations (DI), previously named delusions of parasitosis, have a fixed, false belief that they are infested with living or non-living pathogens. Patients have abnormal cutaneous symptoms such as itching, biting, or crawling sensations. They often demonstrate self-destructive behavior in an effort to rid the pathogens from under their skin, leading to excoriations, ulcerations, and serious secondary infections. This review article aims to provide an overview of DI including its clinical presentation, diagnosis, and treatment. Strategies on how to establish a strong therapeutic alliance with DI patients are discussed. In addition, antipsychotic medications used in the treatment of DI are described., (© 2013 The International Society of Dermatology.)

When patients with psychodermatologic disorders present in clinic, the dermatologist can refer them to psychiatrists or other mental health care professionals. However, it is often the case that these patients will refuse a psychiatric referral because they either do not believe they have a disorder of psychiatric nature or they feel there is societal stigma associated with psychiatric illness. Therefore, it is essential for dermatologists to understand the common classifications for psychodermatological cases and to know how to optimally treat these patients with pharmacotherapy. The intent of this article is to help guide physicians in understanding the classifications of psychodermatological cases and in managing these conditions with pharmacotherapies. In this article, two classifications for psychodermatological cases are presented, followed by a discussion of medical therapies used to treat the main categories of psychopathologies that are more frequently encountered in dermatology. These include depression, anxiety, delusions, and obsessive-compulsive disorder.