Delusions of parasitosis.

Delusions of parasitosis is a rare psychiatric disorder in which the patient has a fixed, false belief that he or she is infested by parasites. Even though it is a psychiatric disorder, these patients usually present to a dermatologist because they are convinced that they have a dermatologic problem. Patients with delusions of parasitosis generally reject psychiatric referral. The traditional treatment of choice for delusions of parasitosis is the antipsychotic medication pimozide (Orap, Gate Pharmaceuticals, Philadelphia, PA). The use of pimozide has been limited by its adverse effects, most notably extrapyramidal adverse effects. There is now an emerging role for atypical antipsychotics with a safer adverse effect profile in the treatment of delusions of parasitosis. However, the most challenging aspect of managing these patients may be the challenge of establishing rapport in the face of unshakable delusional ideation.