Delusional parasitosis: Worms of the mind.

Delusional parasitosis is an uncommon psychotic illness. Patients often report to dermatologists and physicians for treatment and are brought to psychiatric attention only for associated psychological distress. One such case is discussed in this report.

Delusional parasitosis is an infrequent psychotic illness characterized by an unshaken belief of having been infested by a parasite when one is not.[1] It is also called Ekbom syndrome after the Swedish neurologist Karl Axel Ekbom who did seminal work on this entity.[2]

Delusional parasitosis can be primary, secondary, or organic. Primary delusional parasitosis consists primarily of a single delusional belief of having been infested by parasite and comes under monosymptomatic hypochondriacal psychosis.[3] Secondary delusional parasitosis can occur in the context of other mental disorder like schizophrenia, depression, and dementia. Organic delusional parasitosis occurs secondary to organic illness like hypothyroidism, vitamin B12 deficiency, diabetes, cerebrovascular disease, cocaine intoxication, HIV, allergies, and menopausal state.[4-6]

It is believed that these parasites may be macro parasites like helminthes or smaller parasites like virus or bacteria.[7] In background of this belief, patients may perceive parasites crawling or burrowing into skin.[8] Discrete bruises, nodular pruritis, ulcers, and scars are frequently produced by patient trying to extract the parasite.[5] Patient may injure themselves to get rid of parasites or compulsively gather evidence to present to health professionals for help. They may even bring dust, fibers, scab, or debris excoriated from the skin as evidence for inspection in, for example, a matchbox, often called as “match-box sign.”[8] Morgellons, which refers to cutaneous symptoms like biting, crawling, or stinging sensation, finding fibers on or under skin, and persistent skin lesions, are often seen in delusional parasitosis.[9] They commonly seek attention of dermatologist or physicians and may continue seeking different therapies in search of a cure.[6] Treatment primarily involves use of antipsychotics.[10] It also involves management of primary psychological and medical condition in case of secondary or organic delusional parasitosis respectively.[5]

Our patient manifested with belief of his body having been infested with worms. He held on to his belief regardless of absence of any evidence and exclusion of all possible organic cause. He acted on his belief and had significant psychological distress, which brought him finally to psychiatric attention. Generally, such patient presents in 56th decade with such problems. Our patient here presented with these distressing symptoms in his 4th decade. The present case has its salience in rarity of illness, nature of presentation, and effective management.

CASE REPORT

A 36-year-old male was apparently asymptomatic until August 16, 2011, when, in the background of vague sensation of something crawling under his skin, he developed a sudden onset belief that he has been infested by worms that crawl under his skin as well as travel throughout his body. Over next few days, he experienced these sensation again with which he reinforced his belief to an unshakeable level of delusion, although there were no physical feature suggestive of an infestation or any logical ground for holding his belief with such conviction. He started pinching his skins to get hold of those worms. He believed these worms to be of 3-7 cm in length and numerous in numbers. He believed that these worms were biting him, damaging his internal organ, and eating his bone and that they would finally kill him. He became fearful and sought help from a physician. He was prescribed tablet albendazole, which provided him no relief. He further consulted another physician. Routine hemogram and urinalysis was unremarkable. He was given antihelminthic and antiallergens to no relief. He was counseled that he does not have an infestation and his complaints had no physical explanation; however, he held on to his belief regardless. He lost his appetite, remained anxious, and slept less. He was noted by his treating physician to be dull and withdrawn, which led to the psychiatric referral. There was history of hepatitis A 2 months back, which had responded to management by physician and local faith healer. There was no history of pruritis during and after the recovery from hepatitis. There was no past or family history of any neurological, psychiatric, endocrinal, chronic, or allergic illness. He consumed alcohol occasionally. There was no history of any other substance abuse. Physical examination on admission did not reveal any feature of active hepatitis or thyromegaly. Systemic examination was within normal limit. Skin examination revealed itch marks and skin excoriations both the limbs and on other accessible parts of the body. Mental status examination revealed anxious and depressed affect, delusion of parasitosis, tactile hallucination, impaired insight, and reduced biodrives in a clear sensorium. He was admitted in the psychiatry ward for inpatient management. Serial evaluation and ward observation revealed persistent delusion of parasitosis, delusional, and hallucinatory behavior of picking the skin in an attempt to catch the worm, intermittent wincing as he felt worms bit him, secondary depressive cognition, initial insomnia, and reduced appetite. Relevant investigations including hemogram, urinanalysis, fecal analysis, thyroid function, liver function, VDRL, blood sugar, ultrasonography abdomen, viral marker for active hepatitis, electroencephalogram, and computed tomography of the brain was within normal limit. He was also evaluated by dermatologist and physician for evaluation and exclusion of any organicity. He was subsequently diagnosed as a case of persistent delusional disorder (monosymptomatic hypochondriacal psychosis-delusional parasitosis) as per International Classification of Disease (ICD-10-DCR) and managed with typical antipsychotic trifluperazine (10 mg/day), eclectic psychotherapy, and other supportive measures. His delusion and hallucination subsided over the next 2 weeks. He was discharged after 5 weeks on maintenance medication. He has subsequently been asymptomatic and euthymic. Presently, he is asymptomatic since last 7 months and been regular on monthly reviews.

DISCUSSION

Our patient here had delusional parasitosis, which is an uncommon condition. He presented at an age of 39 years. Literature suggest the mean age of the presentation to be more than this.[11] The onset was insidious, lasted more than 6 months and involved the whole body. Bhatia et al., in his series of 52 cases also find similar presentation to be common in this not so common an illness.[12] Most of the reports are from the dermatologic literature and the exact prevalence is not known.[6] Patient sought treatment primarily from physicians and could come to psychiatric attention only when he presented with depressive feature secondary to his delusional belief. Most of these patients are known to seek care of non-psychiatric medical professionals, who may not have the patience or the expertise to treat psychiatric illness.[13] Inappropriate belief, normal relevant investigations, and poor response to standard treatment for parasitic infestation should alarm physicians of the possibility of delusional parasitosis. Many patients become hostile or violent when their infestations are denied.[6] A skill-full approach, good rapport, and empathy was maintained during history taking and management of the patient. Few medical illnesses are known to cause similar delusions. Proper medical evaluation and judicious yet detailed investigation is important for right treatment. All relevant investigations and related specialists opinion were sought to exclude known organic causes. He responded well to treatment, thus preventing further agony and undue medical consults or healthcare burden. He remitted with institution of typical antipsychotics. Although there is no randomized trials in this direction, best evidence suggest equal rate of remission with both typical and atypical antipsychotics to the tune of 60-100%.[10] Ironically and interestingly, phenothiazine derivatives that are used for treatment of delusional parasitosis were once developed from antihelminthic drugs.[14]

To conclude, delusional parasitosis often would present to nonpsychiatric medical professional. They might seek multiple consult to seek relief and would vehemently refuse psychiatric explanation of the symptoms. Poor response to nonpsychiatric treatment, healthcare cost, and significant distress may lead to secondary depressive features compounding the situation. Better awareness of such illness by general physician, early recognition, good rapport, timely referral, and empathic treatment are the cornerstones of management in such cases.