Published online Mar 26, 2022. doi: 10.12998/wjcc.v10.i9.2858
Peer-review started: September 9, 2021
First decision: December 9, 2021
Revised: December 16, 2021
Accepted: January 22, 2022
Article in press: January 22, 2022
Published online: March 26, 2022
Processing time: 194 Days and 0.6 Hours
Delusional parasitosis is characterized by a false belief of being infested with parasites, insects, or worms. This illness is observed in patients with Parkinson’s disease and is usually related to dopaminergic treatment. To our knowledge, no cases of delusional parasitosis have been reported as a premotor symptom or non-motor symptom of Parkinson’s disease.
A 75-year-old woman presented with a complaint of itching that she ascribed to the presence of insects in her skin, and she had erythematous plaques on her trunk, arms, buttocks, and face. These symptoms started two months before the visit to the hospital. She took medication, including antipsychotics, with a diagnosis of delusional parasitosis, and the delusion improved after three months. A year later, antipsychotics were discontinued, and anxiety and depression were controlled with medication. However, she complained of bradykinesia, masked face, hand tremor, and mild rigidity, and we performed fluorinated N-3-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl) nortropane positron emission tomography (PET), which showed mildly decreased DAT binding in the right anterior putamen and caudate nucleus. Parkinson’s disease was diagnosed on the basis of PET and clinical symptoms.
In conclusion, delusional parasitosis can be considered a non-motor sign of Parkinson’s disease along with depression, anxiety, and constipation.
Core Tip: Cases of delusional parasitosis during medication, such as dopamine agonists, in Parkinson’s disease have been reported. However, this case report shows that delusional parasitosis occurred before the diagnosis of Parkinson’s disease. In addition, unlike in other treatments for delusional disorders, the patient’s delusions improved quickly. After delusional parasitosis improved, the motor symptoms of Parkinson’s disease were observed, and Parkinson’s disease was diagnosed. The sudden onset of delusional parasitosis in elderly without a psychiatric history could be associated with the premotor or non-motor symptoms of Parkinson’s disease. Therefore, an evaluation of Parkinson’s disease should be considered for elderly with delusional parasitosis.