Iatrogenic delusional infestation: an observational study

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.

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.

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.

Delusional infestation. Ekbom´s syndrome in a 47-year-old woman. Case report

Introduction: Delusional infestation is a rare psychiatric disorder defined as a condition in which the patient has the unshakable belief and perception of being infested with parasites. Its treatment is difficult, and frequently includes antipsychotic medications (such as olanzapine or aripiprazole). Non-pharmacological treatment, particularly psychotherapy, can be used for less severe cases. Dermatologists and psychiatrists must take a multi-disciplinary approach (preferably in a psycodermatology dedicated clinic) since this type of patients sometimes refuse treatment.Case description: A 53-year-old female businesswoman describes a clinical history of five years of visual hallucinations, depressive symptoms, and generalized pruritus, along with the use of toxic substances to “clean” her skin and cloths. She reports similar symptoms in some relatives but they were not evaluated. Blood tests and analyses of the “specimen” brought by the patient were performed, yielding negative results. The patient had never been assessed by any specialist, and showed disoriented during the consultation. Follow-up was not possible due to the reluctance of the patient to follow the indications and seek psychiatric treatment. Moreover, the patient did not respond to further communication attempts.Discussion: Delusional infestation is an uncommon disease that endangers the patients and the people around them. Its treatment is difficult and long, and not conducting proper follow-up is a great risk. Its prevalence and incidence is variable and generally unknown. It can affect the patient, their next of kin, pets or the environment, and the “pathogen” can be a living organism or an inanimate object.  Conclusion: This case is important as it shows the hardships of treatment, adequate follow-up and care, as well as the need to improve how these patients are approached. Additionally, both classical and uncommon signs and symptoms could be observed as the patient stated that her relatives were affected (possible delusional infestation by proxy).