Delusional parasitosis as presenting symptom of occipital lobe cerebrovascular accident

Delusional parasitosis manifests as a fixed, false belief that an individual is infested by living organisms. Primary delusional parasitosis is a psychiatric disorder with the delusion as an isolated manifestation, whereas secondary delusional parasitosis is a delusion occurring secondary to a psychiatric disorder, substance use, or medical illness. A 62-year-old woman with no psychiatric history presented to the Emergency Department with two to three months of "whole body itching" and seeing small insects crawling on her skin and in her hair. Exam of her skin and scalp was notable for no appreciable lesions, rashes, excoriations, or insects. Her neurologic exam was notable for full visual fields, and no localizing deficits. A non-contrast head CT demonstrated a nonspecific heterogeneous low-attenuation lesion within the medial right occipital lobe, and a follow up MRI confirmed a right posterior cerebral artery distribution subacute infarction. She was admitted for two days, and ultimately was discharged on aspirin and atorvastatin for secondary prevention. An emergency physician should remain vigilant in his/her assessment of patients with seemingly psychiatric symptoms, in particular elderly patients with no known psychiatric illnesses. Neuroimaging should be amongst studies considered in the evaluation of elderly patients presenting with new onset psychiatric complaints.