Dermoscopy is a hitherto unreported aid for examining the artifacts that patients with delusions of parasitosis present to their physicians. A dermatoscope can be quickly attached to a digital camera and the nature of the specimens can be verified. Unfortunately, it is difficult to dissuade these patients of their delusions. Patients with delusions of parasitosis often doctor-shop when their clinicians do not accept their theories of infestation. Medications such as opioids and cocaine can occasionally precipitate formications (the feeling of bugs crawling on his skin) and this man’s high doses of oxycodone may well be related to his fixed ideas.
Smith MJ, Thirthalli J, Abdallah AB, Murray RM, Cottler LB. Prevalence of psychotic symptoms in substance users: a comparison across substances. Compr Psychiatry. 2009 May-Jun;50(3):245-50. Epub 2008 Sep 23. Full Text.
Case 2 March 20, 2012
The patient is a 56 year old carpenter with a ten month history of matter being extruded from his groin and scrotum. He feels this is coming from his skin but does not specify the nature of the artefacts. He is very guarded and suspicious of me. He states he does not belong in a skin clinic, but that is where his internist sent him. For the past few months he has been treated with a variety of antifungal creams. He had a bovine aortic valve replacement done a year ago. He presented specimens on a paper towel in a zip-lock baggie. A dermoscopic picture was taken (see below) and when he was told that the material looked like it could have come from the fibers of his blue jeans, he got defensive and left the office a few moments later saying he'd get other opinions. There is one report of Delusions of Parasitosis after cardiac surgery in the literature. What is the risk/benefit relationship of the antipsychotics used to treat this disorder? He is, after all at this time, able to work. It's remarkable how similar this dermoscopic image is to the previous one. In another culture, shamanism might help these people.
See: W.B. Shelley,E.Dorinda Shelley Delusions of parasitosis associated with coronary bypass surgery. British Journal of Dermatology v. 118, p. 309-10, February 1988