Delusional Parasitosis, OR Delusory Parasitosis, OR Ekbom's syndrome, is a form of psychosis.
Victims acquire a strong delusional belief that they are infested with parasites, whereas in reality no such parasites are present. Often, exposure to household cleaning products can result in a sensation known as formication.
This irritation combined with underlying psychiatric or psycho-pharmacological issues can cause delusional parasitosis.
The false belief of delusional parasitosis stands in contrast to actual cases of parasitosis, such as scabies and infestation with Demodex.
The alternative name of Ekbom's syndrome derives from Swedish neurologist Karl Axel Ekbom, who published seminal accounts of the disease in 1937 and 1938. It is important not to confuse or interchange this with Willis-Ekbom Disease (or WED), another name for restless legs syndrome.
Signs and symptoms
Details of delusional parasitosis vary among sufferers, but it is most commonly described as involving perceived parasites crawling upon or burrowing into the skin, sometimes accompanied by an actual physical sensation (known as formication). Sufferers may injure themselves in attempts to be rid of the "parasites". Some are able to induce the condition in others through suggestion, in which case the term folie à deux may be applicable.
Nearly any marking upon the skin, or small object or particle found on the person or his clothing, can be interpreted as evidence for the parasitic infestation, and sufferers commonly compulsively gather such "evidence" and then present it to medical professionals when seeking help. This presenting of "evidence" is known as "the matchbox sign" because the "evidence" is frequently presented in a small container, such as a matchbox.
A study conducted of 108 patients at the Mayo Clinic was published in Archives of Dermatology on May 16, 2011. The study failed to find evidence of skin infestation despite doing skin biopsies and examining specimens provided by the patients. The study, which was conducted between 2001 and 2007, concluded that the feeling of skin infestation was delusional parasitosis.
Delusional parasitosis is seen more commonly in women, and the frequency is much higher past the age of 40.
Delusory cleptoparasitosis is a form of delusion of parasitosis where the person believes the infestation is in their dwelling, rather than on or in their body.
Diagnosis.
Delusional parasitosis is divided into:
primary,
secondary functional and
secondary organic groups.
Primary
In primary delusional parasitosis, the delusions comprise the entire disease entity: there is no additional deterioration of basic mental functioning or idiosyncratic thought processes. The parasitic delusions consist of a single delusional belief regarding some aspect of health. This is also referred to as "monosymptomatic hypochondriacal psychosis", and sometimes as "true" delusional parasitosis. In the DSM-IV, this corresponds with "delusional disorder, somatic type".
Secondary functional
Secondary functional delusional parasitosis occurs when the delusions are associated with a psychiatric condition such asschizophrenia or clinical depression.
Secondary organic
Secondary organic delusional parasitosis occurs when the state of the patient is caused by a medical illness or substance (medical or recreational) use. In the DSM-IV this corresponds with "psychotic disorder due to general medical condition".
Physical illnesses that can underlie secondary organic delusional parasitosis include:
hypothyroidism,
cancer,
cerebrovascular disease,
tuberculosis,
neurological disorders,
vitamin B12 deficiency, and diabetes mellitus.
Any illness or medication for whichformication is a symptom or side effect can become a trigger for underlying cause of delusional parasitosis.
Other physiological factors which can cause formication and thus can sometimes lead to this condition include:
menopause (i.e. hormone withdrawal);
allergies, and
drug abuse,
including but not limited to cocaine and methamphetamine (as in amphetamine psychosis).
It appears that many of these physiological factors, as well as environmental factors such as airborne irritants, are capable of inducing a "crawling" sensation in otherwise healthy individuals; however, some people become fixated on the sensation and its possible meaning, and this fixation may then develop into delusional parasitosis.
Treatment
Treatment of secondary forms of delusional parasitosis are addressed by treating the primary associated psychological or physical condition. The primary form is treated much as other delusional disorders and schizophrenia. In the past, pimozide was the drug of choice when selecting from the typical antipsychotics. Currently, atypical antipsychotics such as olanzapine orrisperidone are used as first line treatment.
However, it is also characteristic that sufferers will reject the diagnosis of delusional parasitosis by medical professionals, and very few are willing to be treated, despite demonstrable efficacy of treatment.
Victims acquire a strong delusional belief that they are infested with parasites, whereas in reality no such parasites are present. Often, exposure to household cleaning products can result in a sensation known as formication.
This irritation combined with underlying psychiatric or psycho-pharmacological issues can cause delusional parasitosis.
The false belief of delusional parasitosis stands in contrast to actual cases of parasitosis, such as scabies and infestation with Demodex.
The alternative name of Ekbom's syndrome derives from Swedish neurologist Karl Axel Ekbom, who published seminal accounts of the disease in 1937 and 1938. It is important not to confuse or interchange this with Willis-Ekbom Disease (or WED), another name for restless legs syndrome.
Signs and symptoms
Details of delusional parasitosis vary among sufferers, but it is most commonly described as involving perceived parasites crawling upon or burrowing into the skin, sometimes accompanied by an actual physical sensation (known as formication). Sufferers may injure themselves in attempts to be rid of the "parasites". Some are able to induce the condition in others through suggestion, in which case the term folie à deux may be applicable.
Nearly any marking upon the skin, or small object or particle found on the person or his clothing, can be interpreted as evidence for the parasitic infestation, and sufferers commonly compulsively gather such "evidence" and then present it to medical professionals when seeking help. This presenting of "evidence" is known as "the matchbox sign" because the "evidence" is frequently presented in a small container, such as a matchbox.
A study conducted of 108 patients at the Mayo Clinic was published in Archives of Dermatology on May 16, 2011. The study failed to find evidence of skin infestation despite doing skin biopsies and examining specimens provided by the patients. The study, which was conducted between 2001 and 2007, concluded that the feeling of skin infestation was delusional parasitosis.
Delusional parasitosis is seen more commonly in women, and the frequency is much higher past the age of 40.
Delusory cleptoparasitosis is a form of delusion of parasitosis where the person believes the infestation is in their dwelling, rather than on or in their body.
Diagnosis.
Delusional parasitosis is divided into:
primary,
secondary functional and
secondary organic groups.
Primary
In primary delusional parasitosis, the delusions comprise the entire disease entity: there is no additional deterioration of basic mental functioning or idiosyncratic thought processes. The parasitic delusions consist of a single delusional belief regarding some aspect of health. This is also referred to as "monosymptomatic hypochondriacal psychosis", and sometimes as "true" delusional parasitosis. In the DSM-IV, this corresponds with "delusional disorder, somatic type".
Secondary functional
Secondary functional delusional parasitosis occurs when the delusions are associated with a psychiatric condition such asschizophrenia or clinical depression.
Secondary organic
Secondary organic delusional parasitosis occurs when the state of the patient is caused by a medical illness or substance (medical or recreational) use. In the DSM-IV this corresponds with "psychotic disorder due to general medical condition".
Physical illnesses that can underlie secondary organic delusional parasitosis include:
hypothyroidism,
cancer,
cerebrovascular disease,
tuberculosis,
neurological disorders,
vitamin B12 deficiency, and diabetes mellitus.
Any illness or medication for whichformication is a symptom or side effect can become a trigger for underlying cause of delusional parasitosis.
Other physiological factors which can cause formication and thus can sometimes lead to this condition include:
menopause (i.e. hormone withdrawal);
allergies, and
drug abuse,
including but not limited to cocaine and methamphetamine (as in amphetamine psychosis).
It appears that many of these physiological factors, as well as environmental factors such as airborne irritants, are capable of inducing a "crawling" sensation in otherwise healthy individuals; however, some people become fixated on the sensation and its possible meaning, and this fixation may then develop into delusional parasitosis.
Treatment
Treatment of secondary forms of delusional parasitosis are addressed by treating the primary associated psychological or physical condition. The primary form is treated much as other delusional disorders and schizophrenia. In the past, pimozide was the drug of choice when selecting from the typical antipsychotics. Currently, atypical antipsychotics such as olanzapine orrisperidone are used as first line treatment.
However, it is also characteristic that sufferers will reject the diagnosis of delusional parasitosis by medical professionals, and very few are willing to be treated, despite demonstrable efficacy of treatment.
