Delusional Parasitosis in Comorbidity With Shared Paranoid Disorder in a Marriage.

Delusional parasitosis is a psychotic disorder where the patient has the delusion of being infested with some insect or parasite. In contrast, shared paranoid disorder or folie à deux is described when the same delusions affect two or more closely related people. It is common for these two situations to cause comorbidity in the family unit. This case report concerns a couple married for 37 years. The husband described that 2 years ago, he began with a tingling sensation throughout his body, related to the presence of parasites coming out from all his body orifices, with no evidence of self-harm. Likewise, the wife reported symptoms of formication and the feeling that there were invisible animals, as mentioned by her husband, and that she felt the parasites running throughout her body. The husband was diagnosed with endoparasitic delusional parasitosis, which caused folie à deux in his wife due to ectoparasitic parasitosis. The patient's treatment included sertraline and risperidone in oral dosage lasting 3 months reducing delirium, later biperidene was prescribed due to main treatment's side effects such as akathisia and sialorrhea, however the patient could not take the medication due to economic reasons. The wife was asked to sleep in a separate room, and she reported that the sensory hallucinations disappeared as soon as she slept in a different room. We conclude that the pharmacological approach, the intervention in the family life, and the gradual reintegration of marital habits once the patient improves are crucial in the therapy of delusional disorder.