Fall 2018 Issue
By Allison Beckmann - MD Candidate 2018
Ryan Wade, MD, MA
Stephanie Peglow, DO, MPH
Delusional Parasitosis (DP) is the fixed or persistent belief of being infected by insects or some other living organism. With this delusion of infection, people often may also experience tactile and/or visual hallucinations. Patients with this disorder frequently exhibit repeated self-examination or painstaking cleansing practices in an attempt to remove the parasite. This behavior may lead to skin lesions, further reaffirming their belief of an infection.1
Diagnosis of a patient with DP is not typically immediate, as a person first seeks aid from other physicians, such as dermatologists, to treat their skin infections, rashes, and to eliminate their perceived parasites. Years may pass before a physician recognizes the patient has a psychiatric disorder.
The demographics of patients with DP are atypical when compared to most psychiatric disorders in that these patients are often well educated, middle-aged adults, with the mean age of onset being 61.4 years.2 Frequently, these patients are pet owners. Five to fifteen percent of patients with delusional parasitosis have it as a result of folie a deux, in which case, the disorder is often shared with spouses or close relatives.3 This is more common with regard to the somatic symptoms of the delusion.
Delusional Parasitosis can be primary in origin, where it presents in isolation, or as a result of a secondary cause, such as other psychiatric disorders, general medical conditions, therapies, or recreational substances. The disorder can also be episodic or chronic, with the mean duration lasting three years. Primary DP is typically chronic.1
The main theory behind this disorder is described as decreased striatal dopamine transporter (DAT) functioning, corresponding with an increased extracellular dopamine level. This theory was revealed in case reports where cocaine, methylphenidate and other amphetamine-derivatives have induced the clinical expression of DP. Also supporting this theory is the treatment of DP with dopamine inhibitors.4 Pimozide has been shown to have the highest efficacy in treating DP and is often the preferred treatment; but olanzapine or risperidone can be used as first line treatment if an atypical antipsychotic is preferred.5
Delusional Parasitosis is chronically underdiagnosed as many people live with the disorder without the knowledge that the syndrome is psychotic. Spreading education and knowledge of the symptoms and presentation of DP can help to identify and treat more individuals with this ailment.
September 28-29, 2018
Stonewall Jackson Hotel
Are you accepting new patients?
Opt into APA’s “Find A Psychiatrist” database. To view the functionality or opt-in, CLICK HERE
FYI: A link for this option has been added to the PSV website. Select the “About” button and then “Find a Psychiatrist” from the drop down.