British Association of Dermatologists guidelines for the management of adults with delusional infestation 2022

Delusional infestation treated with risperidone: a series of 27 patients

BACKGROUND

Patients with delusional infestation (DI) frequently refuse to be treated with psychoactive drugs. In the past, pimozide was commonly used as a first-line agent but is now prescribed more rarely. Risperidone was first used to treat DI in 1995. A recent review identified 12 studies that evaluated the use of risperidone in 43 patients with DI.

OBJECTIVES

To study the characteristics of and therapeutic results in patients with DI treated with risperidone at a university medical centre in São Paulo, Brazil.

METHODS

We performed a retrospective study of patients with DI treated with risperidone at a dermatological university clinic since 2016. Records were reviewed for personal data and findings related to treatment.

RESULTS

Twenty-seven patients were studied (20 women and 7 men). The maintenance dose of risperidone varied from 1 mg three times weekly to 8 mg daily. Control of symptoms was achieved in the majority of patients. A reduction in dosage due to side-effects was seen in four patients; risperidone had to be switched to another antipsychotic in three cases, despite a good response. Only one patient did not respond to risperidone.

CONCLUSIONS

Risperidone is an effective, well-tolerated and safe treatment for delusional parasitosis. Adequate follow-up is mandatory in order to obtain long-term control of symptoms.

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: 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.

Pharmacological Interventions for Primary Psychodermatologic Disorders: An Evidence Mapping and Appraisal of Randomized Controlled Trials

BACKGROUND

The lack of clinical guidelines for the treatment of primary psychodermatologic disorders (PPDs) hinders the delivery of optimal care to patients. The review aimed to identify, appraise, and summarize the currently available evidence about the safety and effectiveness of pharmacological management of PPDs through randomized controlled trials (RCTs).

METHODS

The Preferred Reporting Items for Systematic Review and Meta-Analyses (PRIMSA) statement and the Global Evidence Mapping Initiative guidance were followed. Medline, Embase, PsycInfo, Cochrane and Scopus were searched, and two reviewers independently completed article review, data extraction, and quality assessment.

RESULTS

Among 2618 unique studies, full texts of 83 were reviewed and 21 RCTs were included. Five PDDs were identified: trichotillomania (n = 12), pathologic skin picking (n = 5), nail biting (n = 2), delusional parasitosis (n = 1), and dermatitis from compulsive hand washing (n = 1). Seven different classes of medications were investigated: SSRIs (i.e., fluoxetine, sertraline, and citalopram), tricyclic antidepressants (i.e., clomipramine and desipramine), antipsychotics (i.e., olanzapine and pimozide), anticonvulsant (i.e., lamotrigine), N-acetylcysteine, inositol, and milk thistle. RCT-derived evidence supports the use of antidepressants in trichotillomania (sertraline and clomipramine), pathologic skin picking (fluoxetine), pathologic nail biting and dermatitis from compulsive hand washing (clomipramine or desipramine); antipsychotics in trichotillomania (olanzapine) and delusional parasitosis (pimozide); N-acetyl cysteine in trichotillomania and skin picking.

CONCLUSION

Few pharmacotherapies for primary psychodermatologic disorders are assessed through controlled trials in the literature. This review serves as a roadmap for researchers and clinicians to reach informed decisions with current evidence, and to build on it to establish guidelines in the future.