Contributor: Taylor Lynch, MD Educational Pearls: Delusional parasitosis is a subtype of the psychiatric condition delusional disorder Defined as a fixed, false belief of infestation by parasites or other organisms A somatic type of delusional disorder Primary delusional parasitosis Occurs in the absence of other psychiatric or medical conditions Secondary delusional parasitosis Causes include methamphetamine use disorder, schizophrenia, neurologic diseases, or medical conditions such as thyroid disease Pathophysiology Poorly understood Upregulation of striatal dopamine system is implicated Management Form a strong therapeutic alliance and do not discredit the patient immediately Perform a full physical exam This helps reassure the patient and strengthen the therapeutic alliance Some day there may be a patient in whom this is not a delusion Treatment & Management Discontinuation of substances if substance-induced Antipsychotic medications like risperidone or olanzapine References Lepping P, Russell I, Freudenmann RW. Antipsychotic treatment of primary delusional parasitosis: systematic review. Br J Psychiatry. 2007;191:198-205. doi:10.1192/bjp.bp.106.029660 Moriarty N, Alam M, Kalus A, O'Connor K. Current Understanding and Approach to Delusional Infestation. Am J Med. 2019;132(12):1401-1409. doi:10.1016/j.amjmed.2019.06.017 Skelton M, Khokhar WA, Thacker SP. Treatments for delusional disorder. Cochrane Database Syst Rev. 2015;2015(5):CD009785. Published 2015 May 22. doi:10.1002/14651858.CD009785.pub2 Summarized and Edited by Jorge Chalit, OMS4 Donate : https://emergencymedicalminute.org/donate/
