Delusional parasitosis [abstract]

ABSTRACT

Delusional parasitosis is a rare psychiatric syndrome in which the patient believes that he/she is infested with parasites despite clear evidence to the contrary. It was first described in the literature about 100 years ago when it was referred to as psychogenic parasitosis. It can occur in the form of a delusional disorder of the somatic type (DSM IV) but it has also been reported in schizophrenia, affective or organic psychosis or induced psychosis. Patients with delusional parasitosis generally think that mites, lice or other insects have invaded their skin and most frequently seek treatment from dermatologists or family practitioners. It is a chronic disorder that may occur at any age but is more common in the elderly, particularly in females. The patient may try to pick the parasites out of the skin causing cutaneous lesions. Treatment is based on antipsychotic agents, psychotherapy and cooperation between dermatologist and psychiatrist. A case of delusional disorder of the somatic type (DSM IV) in a 55-year-old male is described. The patient sought medical attention because he strongly believed that his skin was infested with mites for three years. He tried to pick mites out of the skin of his face, neck, abdomen and back and this caused severe keloid formation. He was first seen by a dermatologist whose clinical and laboratory investigations for parasitic infestations were negative. After investigation, the patient was referred to the psychiatrist. Haloperidol was prescribed and there was good response to antipsychotic treatment. The delusional symptoms improved over the first three months and then a full recovery was observed. The patient maintained the recovery at one-year follow-up. (AU)