Delusional parasitosis, first documented in 1946, is a rare psychiatric illness described as both a stand-alone diagnosis, as well as a secondary condition to an underlying psychiatric or medical pathology, or substance use. Interestingly, the fixed false belief of being infested has also been identified in partners of individuals with the disease, and in some cases the delusion permeated families and was thus given the name “folie en famille”.

To describe the first reported case of delusional disorder, somatic type, with similar delusional symptoms in the patient’s husband, in the State of Qatar.

Patient and her husband were interviewed. Her file was reviewed for past history and medications.

34-year-old female with no past psychiatric history, 5 months post-partum, reported fixed beliefs of insect infestation in her baby’s skin, hers, and her husband’s, of 2 months duration. She reports a pruritic rash, and perceives proliferating insects in different life stages. The family relocated 5 times in 2 months. They bathe in vinegar several times a day to exterminate the insects. Husband mirrors her account of infestation with milder symptoms. Repeated medical investigations were insignificant. OCD, mood disorder, and other psychotic illnesses were ruled out.

Delusional parasitosis presents a unique therapeutic challenge to psychiatrists. It is necessary to build rapport with patients, rule out comorbidities, and conduct randomized controlled trials to evaluate the effectiveness of psychotropic drugs in its treatment. In cases of shared delusions, identifying the primary patient is crucial for treatment of all the individuals that share the delusion.

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Antipsychotics are the mainstream treatment of delusional disorder. However, limited therapeutic effect was recognized due to side effect and lack of insight.

This article presents a case with Ekbom’s syndrome, also known as delusional parasitosis, who has significant response with Brexpiprazole.

A 58-year-old female developed her very first episode of psychosis 3 weeks before she visited our emergency department. Delusion of spiders laying eggs and bitsy spiders crawling over her body was claimed, followed by depressed mood and insomnia. The patient denied any substance use in recent months. Examination including biochemical studies, complete blood count, vitamin, and endocrine during admission were all normal. Brain image revealed senile cortical atrophy without apparent acute infarction. Cognitive abilities screening instrument (CASI) revealed total score 75, indicating borderline cognitive function. Ophthalmologist and dermatologist were consulted, and no specific abnormality was found.

Brexpiprazole 2mg was prescribed. After 3 weeks of treatment, the delusion improved with less parasitosis content. We discharged the patient, and kept following her at outpatient department with Brexpiprazole 2mg for 2 months. We tried to taper Brexpiprazole to 1mg at clinic, but her delusional parasitosis relapsed within 1 month. Therefore, we titrated the medication back to 2mg, and kept some dosage for 4 months. No more relapse of psychosis or significant movement dysfunction was observed. The total treatment course was 7 months.

Brexpiprazole, with its D2 partial agonism, shows impressive antipsychotic effect to Ekbom’s syndrome. Little side effect was observed in clinical practice, making Brexpiprazole a worth-trying psychopharmacological management of delusional parasitosis.

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A delusion of parasitosis is defined as the fixed, false belief of infestation by invisible organisms or fibrous material of unknown origin. The differential diagnosis is true infection, substance use disorder, dementia or other neuropsychiatric disease.

Our goal was to characterize delusions of parasitosis, classically named Ekbom syndrome, among individuals attending our emergency department (ED).

Over a four-year period (2017-2020), we carried out a retrospective case-register study of patients with DSM-5 Ekbom syndrome attending an ED that provides mental health services to an area of nearly 450.000 inhabitants in Sabadell (Barcelona, Spain).

There were 13 eligible patients: 7 were diagnosed for the first time and 6 had multiple episodes. Female-to-male ratio was 1.6:1; average age was 56.9. The most common diagnosis was delusional disorder (n=5;8.5%), followed by schizophrenia (n=3;23.1%) and organic disorders (n=2;15.4%). Origin: Africa (n=5;38.5%), South-America (n=4;30.8%) and Spain (n=4;30.8%). Fifty percent showed poor treatment compliance. Antipsychotics used: risperidone (n=8;61.54%), olanzapine (n=4;30.8%). Five patients received antidepressants. Most patients had previously been seen by other medical specialties (internal medicine, dermatology and hematology). ‘’Match box sign’’: 7 patients (53.8%). Cerebral atrophy was present on brain scan in 4 patients. After discharge: acute psychiatric unit (n=7), outpatient appointments (n=4), day hospital (n=1) and 1 to a psychogeriatric unit.

Delusions of parasitosis are rare in our emergency department. The typical patient is a postmenopausal woman, a visitor or immigrant to Spain. Effective treatment requires a focus on cultural, gender, and age aspects, with close cooperation between psychiatry and other relevant specialties.

Delusional parasitosis/infestation or Ekbom syndrome is an uncommon psychotic disorder characterized by a false belief that there is a parasitic infestation of the skin - the delusion that insects are crawling underneath the skin.

This work aims to summarize and evaluate the currently available evidence regarding Delusional parasitosis, and for this purpose, we will illustrate a case report of a patient admitted in the emergency room.

The authors have conducted online research in PubMed with the words “Delusional parasitosis” “delusional infestation”, “Ekbom syndrome”, from the outcome, the articles considered to be relevant were collected and analyzed.

Delusional parasitosis can be classified into primary delusional parasitosis without other psychiatric or organic disorders present, secondary – functional (secondary to several mental disorders such as schizophrenia, depression, dementia, anxiety, and phobia), and organic forms (associated with hypothyroidism, anaemia, vitamin B12 deficiency, hepatitis, diabetes, infections (e.g., HIV, syphilis), and cocaine abuse. It is most commonly seen in middle-aged women. The patients became frequently socially isolated, prone to the development of depression symptoms.

This syndrome often presents a high level of psychosocial morbidity. Patients often seek dermatologists help in the first place, although there is no medical evidence. Psychiatrists play a major role in the diagnosis and treatment of these patients. Psychopharmacological therapy is quite challenging because of the patient’s belief that they have a parasitic infestation and not a psychiatric condition.

Delusional parasitosis (DP), also know as Ekbom syndrome and in some cases as Morgellons, was first described in the late 17th century in France. It is an obsessive phobic state in which the patient believes that the is infested by parasites. In the hallucinatory state, they frequently remove parts of the skin, identifying them as parasites. The cause of DP is unknown. Evidence supporting the dopamine theory defend that the inhibition of dopamine reuptake (for example cocaine and amphetamines) induce symptoms such as formication.

Through the description of the following clinical case, we emphasize its clinical features and complexities.

Review of DP in light of a clinical case

A 48-year-old woman was brought to the psychiatric emergency due to psychotic symptoms following cocaine use. She had a history of drug abuse. She was apparently asymptomatic until October 2019, when, in the background of vague sensation of something crawling under his skin, she developed a sudden onset belief that she had been infested by insects that crawled under his skin. Previous medical observation found no reason for a skin infection or infestation. Skin examination revealed itch marks and skin excoriations in the abdomen. Mental status examination revealed anxious and depressive affect, delusion of parasitosis, tactile hallucination and impaired insight. Routine hemogram and urinalysis was unremarkable, except for the detection of cocaine.

Delusional parasitosis often presents to nonpsychiatric medical professionals. An awareness of such ilness, with an early recognition and timely referral are management cornerstones in order to successfully diagnose and treat patients.

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Delusional infestation (DI), also known as delusional parasitosis or Ekbom syndrome, is a rare disorder, characterised by fixed belief that the skin, body or immediate environment is infested by small pathogens, despite the lack of any medical evidence for it.

To describe and discuss two clinical cases of DI, in order to show two different ways of presenting in this entity.

Two case report and non-systematic review.

We present the case of a 76-year-old woman, without psychiatric history, with an DI with 5 years of evolution, referred to a psychiatric consultation by a dermatologist. The second case, is a 41-year-old woman with a history of multiple substance use disorder, with an DI with a month of evolution, who resorted to the emergency department. DI is not a single diagnostic entity. The classic form, as represented in the first case,is a primary form, which develops without any known cause or underlying disease, corresponding to a persistent delusional disorder. However, about 60% of patients have secondary forms of DI, in the context of substance misuse, some medications or in the course of physical or psychiatric diseases (e.g. stroke, delirium, dementia, depression, schizophrenia).

DI can occur as a primary delusional disorder or secondary to several other medical conditions. An in-depth clinical history is essential in order to make the correct diagnosis. A multidisciplinary approach is also important, to exclude any possible organic etiology, not forgetting that many patients may turn to other medical specialities first.

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Antipsychotics have been classically considered the treatment of choice for delusional disorder (DD) and antidepressant medications have been restricted to patients with comorbid depression.

Our aim is to describe the case of a patient with DD with delusions of parasitosis, who responded to paroxetine as monotherapy. We also aimed to review the recent literature on the potential use of antidepressants as the main treatment for somatic type DD.

After the case report, we present a narrative review on the use of antidepressants in DD, somatic type (DSM-criteria) by using PubMed database from inception until 2020.

Case: 74 year-old woman without previous psychiatric diagnosis who suffered from long-term cutaneous and vulvar pruritus. She was referred to psychiatry from dermatology to assess thought content and sensoperceptive disturbances. In the past, she had received unsuccessful treatment with antihistamines. The patient brought a collection of “the identified parasite” (matchbox sign) to our first appointment. On assessment, she was diagnosed with DD with delusions of parasitosis. Risperidone 1mg/day was poorly tolerated (excessive sedation). She refused further antipsychotic treatment, so we started paroxetine up to 20mg/day. The patient went into total remission of her pruritus and delusions of parasitosis. Review. In line with our case, 6 studies reported on the successful use of antidepressants as monotherapy for DD, somatic type. Most of studies report the successful use of an antipsychotic/antidepressant combination (case-series, case reports).

Although antipsychotics are the treatment of choice, antidepressant medications may be an effective alternative in somatic type DD when patients refuse antipsychotics.

Delusional infestation is a condition at the interface of tactile and visual hallucinations and delusions. Individuals with this condition hold the fixed and false belief that their body or their environment is infested with parasites, insects or other organisms.

There are no guidelines or publications detailing the psychological assessment, formulation, intervention and evaluation of this presentation. This paper aims to address this gap.

Single case experimental design methodology was employed to evaluate the use of cognitive behavioural therapy (CBT) for delusional infestation in a 70-year-old male who was intolerant of anti-psychotic medication. ‘Tom’ had a large, mature infarct in the middle cerebral artery territory as well as a left posterior parietal infarct post-stroke, which may have precipitated his symptoms. After a baseline period of 3 weeks, Tom received eight sessions of CBT based on the model by Collerton and Dudley (2004).

Post-intervention, there was a reliable improvement on clinical measures as well as a large reduction in distress levels, which was maintained at 3-month follow-up. The conviction in the belief that the infestation was real did not shift.

This case demonstrated the potential for the use of CBT to address distress related to delusional infestation. This work is discussed in relation to post-stroke psychosis, psychological therapies with older adults, and suggestions are made for future research.