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 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.

No significant relationships.

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.