Delusional parasitosis with folie à deux: A case series

Abstract

Delusional parasitosis (DP) is characterized by single hypochondriacal delusion in which patient feels he/she is infested with insects. The authors present a case series of three cases of DP with shared psychotic disorder (folie à deux) in which one individual developed a delusional belief in the context of a close relationship with another person or people who already had an established delusional idea. All patients of DP were assessed in the outpatient department of Psychiatry of a tertiary care hospital. Diagnosis of DP was made on detail clinical history and supporting clinical findings. All our primary cases had DP and the accompanying relatives of our patients had folie à deux as they shared the belief of parasite infestation which was firm and persisted despite evidence to the contrary. The primary cases of delusional parasitosis responded well to oral risperidone. The intensity of the belief in the secondary person also reduced with improvement in the symptoms of the patients.

Update on pharmacotherapy in psychodermatological disorders

“…In a case series of three DP patients started on risperidone 2mg/day increased upto 4–6mg, good improvement was seen within 3 months. [ 11 ] In another study on DP, a good response was reported in three patients with olanzapine at a dose of 5mg/day increased to 10 mg.[ 12 ] Aripiprazole, considered as a “third-generation antipsychotic,” has also been tried in DP in the dose of 5–10 mg/day. [ 13 ] One distinct advantage of aripiprazole over other SGAs is the absence of weight gain.…”

Inflammatory and Noninflammatory Itch: Implications in Pathophysiology-Directed Treatments

“…Psychogenic pruritus is considered psychiatric in origin and presents as itch in conditions such as obsessive-compulsive disorders, depression, and delusions of parasitosis [ 10 , 11 ]. It is characterized as an excessive impulse to scratch or pick at normal skin.…”

Delusional Infestation

“…Shared delusional infestation is estimated to occur in approximately 5–15% of cases [ 24 ]. In folie à deux , two individuals may concomitantly share a diagnosis of delusional infestation [ 25 ]. Cases of three or more concomitant patients with delusional infestation have been reported.…”