A Case of Delusional Parasitosis With Folie à Deux Treated With Low-Dose Quetiapine.

A patient with a three-month history of persistent delusions of infestation presented to the emergency department with suicidal ideation secondary to complaints of worsening pruritus. Routine investigations failed to disclose any underlying organic cause for her pruritic sensations. The patient ascribed these to a parasitic infestation acquired following a brief stay at her maternal aunt's residence. Following a thorough psychiatric assessment and collateral history obtained from her aunt, it became clear that both the patient and her aunt held similar delusions of infestation. Her aunt was found to be the main inducer. The patient was admitted, successfully treated with low-dose quetiapine, and eventually deemed fit for discharge. Delusional parasitosis and folie à deux are both rare conditions that may sometimes co-occur.