Delusional Parasitosis leading to Self-Injury: Case Report.

Abstract

Delusional parasitosis is a syndrome with which most psychiatrists are familiar. However, most reports consist of case reports or small series. We present here a case report of delusional parasitosiswith self-injury that responded to risperidone and electroconvulsive therapy (ECT).

Keywords

delusional parasitosis, risperidone, self-injury, ECT.

Introduction

Delusional parasitosis (DP) is a delusional disorder characterized by a fixed belief of infestation by parasites, despite a lack of supporting medical evidence [1,2]. DP may involve tactile hallucinations, psychosocial functioning may be variably impaired secondary to the delusion, and the patient attimes may go to any extent to get him rid of the parasitosis [3]. Primary DP is not due to a general medical condition or substance abuse, while secondary DP is related to a variety of medical disorders including stroke, leprosy, peripheral neuropathy, and loss of visual acuity, as well as substance abuse and other psychiatric disorders [4,5]. In the present case report we report a delusional parasitosisthat led to self-injury.

Case Report

A 50 year old right handed printer married with 4 children presented to our outpatient department with a feeling of insect crawling all over his body since 4 months prior to presentation. The patient was apparently alright 4 months prior to his hospital visit when he had a skin rash with itching and pruritis all over his body. The patient visited a skin specialist and was better with the medication prescribed. The patient after that however started feeling that there were insects around 15-20 in number and 2-3cm in size crawling all over his body under the skin. He would initially take a bath three times a day and scrub vigourously to get rid of them. This did not help and since the last two months the insects had localized to the head and neck. The patient on many occasions tried to remove them by putting small sticks inside his ear and even pierced his ear drum in the bargain. He used a blade and would make small slits on his neck and forehead hoping that the insects would come out through them. The patient denied having seeing the insects but was sure that they were present beneath the skin. The insects also led to anxiety in the patient and he displayed lack of interest and concentration at work and would even feel suicidal at times. It was then that he was brought to the psychiatrist for a check up. The delusional nature of his symptoms was established on mental status examination.

Patient was started on antipsychotic drug treatment in the form of Risperidone (4mg/day) andTrihexyphenydyl (2mg/day). He was admitted in the psychiatry ward and the dose of Risperidone increased to 6mg per day. He was given a course of 8 ECT’s in view of the suicidal tendencies he exhibited. The patient was symptomatically better and discharged and asked to follow up on OPD basis for ECTs but he did not do so. His symptoms reduced by 80%, although occasional sensations of worms persisted 2-3 times a week. The patient is maintained on Risperidone and Trihexyphenydyl.

Discussion

DP has been known to occur in the presence of substance abuse and may also be seen in some cases with existing skin disorders [6]. Patients with DP may engage in self injurious behaviour and may scrape or peel their skin when they feel the worms crawling. They may collect the worms and bring specimens to show their doctor often called the ‘match box sign’ [7]. The case we have presented above is an example of DP leading to self injury and suicidal tendencies. DP is a disorder with which every dermatologist, and emergency medicine personnel should become familiar. To date, however, the only effective pharmacologic options are antipsychotic medications. The response to medication is often incomplete and unsatisfactory. No randomized controlled trials or studies are available due to the rarity of the condition [8]. Risperidone, Olanzapine, Haloperidol and Pimozide have all been used extensively [9]. Electroconvulsive therapy may be a viable option when medicines fail and suicidal behaviour is present. A combination of treatments to treat both DP and the existing comorbid psychiatric conditions is often warranted [10].

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