It was only a few months ago that I watched the 2006 film Bug for the very first time. Directed by William Friedkin, it tells the story of a mentally ill drifter called Peter Evans (with a great performance by Michael Shannon). Evans ends up having a sexual relationship with Agnes White, a bisexual alcoholic junkie (played surprisingly well by Ashley Judd). During the film, Peter confides in Agnes his belief that he has a colony of microscopic bugs infested one of his molar teeth (and then in one ‘memorable’ scene starts pulling his own teeth out). Evans’ paranoia becomes increasingly erratic and becomes a shared belief with White (who also comes to believe that they are both infested with microscopic bugs; this sharing of a delusional belief is known as a ‘folie à deux’ [French for ‘a madness shared by two people’, a shared psychosis] and would make a good blog topic). However, today’s blog focuses on imagined bug infestation (i.e., delusional parasitosis) that is known in psychological and psychiatric terms as Ekbom’s syndrome (named after the Swedish neurologist Karl Ekbom who first described the condition in a number of published papers in the late 1930s).
As you have probably gathered from my quick film synopsis above, Ekbom’s syndrome (ES) is a type of psychosis in which sufferers have a vehement delusional belief that they are infested with parasites that those affected describe as bugs or insects crawling around under their skin (when in reality they simply do not exist). I ought to add that the characters in Bug also appeared to be suffering from ‘delusory cleptoparasitosis’ (DC) another type of insect psychosis in which the sufferer thinks the place where they live is infested with parasites (rather than from within their body). As a consequence, both ES and DC sufferers are more likely to seek the help of skin specialists (e.g., dermatologists) and insect specialists (e.g., pest control, entomologists) than psychologists.
In essence, ES is a tactile hallucination and is also known as ‘formication’ (which is the word that describes the feeling of insects crawling and/or burrowing underneath the skin’s surface. Formication is also one form of parasthaesia (of which other examples include the ‘pins and needles’ tingling sensations that many people experience regularly). Parasthaesia includes any non-permanent skin sensation including tickling, pricking, tingling, numbness, and/or burning. ES sufferers will focus on any unusual body mark on their skin as ‘evidence’ that they have a parasitic infection. It is not uncommon for obsessive and/or compulsive checking of the body to occur. The prevalence of ES is unknown although Dr. J. Koo and Dr. C. Gambla reported in the journal Dermatologic Clinic that they see around 20 new cases per year in the large US referral clinic.
In some psychological circles, ES has been used synonymously with Wittmaack-Ekbom syndrome that is more associated with ‘restless leg syndrome’ (RLS; something that I myself have suffered from due to a chronic spinal condition that I have). When I get my bouts of RLS, it really does feel as though I have tiny insects moving about inside my right leg. The difference between ES and RLS is that RLS is a real physical condition that has bona fide physical basis whereas the basis for ES is an imaginary delusion. Clinical and medical research has shown that ES is associated with a number of comorbid conditions including affective psychosis, paranoid schizophrenia, organic brain disease, neurosis, and anankastic/paranoid personality disorder. It has also been reported in some people undergoing alcohol withdrawal, cocaine misuse, cerebrovascular disease, senile dementia, and thalamic brain lesions.
There can also be medical complications for ES sufferers. The fictional example of someone pulling their teeth out is not unknown although the gouging or digging out of the perceived parasites is more common. However, a paper by Dr. M. Nel and colleagues in the Journal of the South African Veterinary Association, most ES sufferers are able to function normally in all other aspects of their lives, in spite of their fixed parasitic delusions. They also noted that:
“The typical history often describes numerous attempts at eradicating the infestation. These could include taking medication, applying topical treatments, using pesticides, making use of exterminators, discarding clothing and possessions and even relocating…In a study of 94 patients (Ohtaki, 1991), most patients complained of itching and/or a tickling sensation. In order to rid themselves of the so-called parasites, patients often scratch, pick and wash frequently or use caustic agents on their skin, almost invariably leading to traumatic skin lesions”.
According to one meta-analytic study of 1,223 ES cases (published by Dr. W. Trabart in the journal Psychopathology), the occurrence of ES as a shared psychotic disorder is an uncommon phenomenon. He reported only about 5-15% of such cases were found. It was also reported that ES was more common amongst females (two-thirds female, one-third male), and is more prevalent in those over the age of 40 years. The symptoms had lasted three to four-and-a-half years. ES can be classified into three sub-types (primary; secondary-functional; and secondary-organic) based on the presenting symptoms:
- Primary ES refers to individuals that have the delusional parasitic infestation but no other comorbid conditions (i.e., other mental functioning is normal). Those where ES occurs by suggestion from another individual (e.g., the folie a deux case mentioned above) would be included in this ES sub-type. (It’s also worth noting that at least three studies have reported either the folie à deux or folie à trois among family members or loved ones including papers in the British Journal of Psychiatry and Dermatologica). Treatment is usually pharmacotherapy-based and utilizes drugs that are used in the treatment of other delusional-based syndromes (e.g., atypical antipsychotic drugs such as risperidone and olanzapine.
- Secondary-functional ES refers to individuals that have the delusional parasitic infestation and are associated with another psychiatric condition (e.g., clinical depression, schizophrenia).
- Secondary-organic ES refers to individuals that have the delusional parasitic infestation that is caused by another medical illness (e.g., cancer, diabetes, tubercolosis, hyperthyroidism, vitamin deficiency, cerebrovascular disease, neurological disorders). Other conditions can also facilitate ES including drug abuse (including stimulant psychosis), various allergies, and the menopause). Treating the primary disorder will often lead to a reduction or elimination of the ES symptoms.
The most recent review of the literature I came across was by Dr. Andrea Boggild and colleagues, and published in a 2010 issue of the International Journal of Infectious Diseases, they concluded that:
“In summary, [delusional parasitosis] is one of the more challenging entities that infectious diseases specialists will be enlisted to help treat. Unfortunately, optimal therapeutic regimens leading to sustained remission are lacking, and assurances on the part of the clinician do little to ameliorate patient suffering”.
Dr Mark Griffiths, Professor of Gambling Studies, International Gaming Research Unit, Nottingham Trent University, Nottingham, UK
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