Delusional parasitosis (DP) is a mental disorder in which individuals have a persistent belief that they are infested with living or nonliving pathogens such as parasites, insects, or bugs, when no such infestation is present. They usually report tactile hallucinations known as formication, a sensation resembling insects crawling on or under the skin. Morgellons is considered to be a subtype of this condition, in which individuals have sores that they believe contain harmful fibers.[1]
Delusional parasitosis is classified as a delusional disorder in the Diagnostic and Statistical Manual of Mental Disorders (DSM5). The cause is unknown, but is thought to be related to excess dopamine in the brain. Delusional parasitosis is diagnosed when the delusion is the only symptom of psychosis and the delusion—that cannot be better explained by another condition—has lasted a month or longer. Few individuals with the condition willingly accept treatment, because they do not recognize the illness as a delusion. Antipsychotic medications offer a potential cure, while cognitive behavioral therapy and antidepressants can be used to help alleviate symptoms.[1]
The condition is rare, and is observed twice as often in women as men. The average age of people with the disorder is 57. An alternative name, Ekbom's syndrome, honors the neurologist Karl-Axel Ekbom, who published seminal accounts of the disease in 1937 and 1938.[1]
Classification
Delusional infestation is classified as a delusional disorder of the somatic subtype in the Diagnostic and Statistical Manual of Mental Disorders (DSM5).[1][2] The name delusional parasitosis has been the most common name since 2015, but the condition has also been called delusional infestation, delusory parasitosis, delusional ectoparasitosis, psychogenic parasitosis, Ekbom syndrome, dermatophobia, parasitophobia, formication and "cocaine bugs".[2]
Morgellons is a form of delusional parasitosis in which people have painful skin sensations that they believe contain fibers of various kinds; its presentation is very similar to other delusional infestations, but people with this self-diagnosed condition also believe that strings or fibers are present in their skin lesions.[1][2]
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.[3]
Signs and symptoms
People with delusional parasitosis believe that "parasites, worms, mites, bacteria, fungus" or some other living organism has infected them, and reasoning or logic will not dissuade them from this belief.[2] Details vary among those who have the condition, though it typically manifests as a crawling and pin-pricking sensation that 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).[1][2][4] Affected people may injure themselves in attempts to be rid of the "parasites"; resulting skin damage includes excoriation, bruising and cuts, as well as damage caused from using chemical substances and obsessive cleansing routines.[4]
A "preceding event such as a bug bite, travel, sharing clothes, or contact with an infected person" is often identified by individuals with DP; such events may lead the individual to misattribute symptoms because of more awareness of symptoms they were previously able to ignore.[1] Nearly any marking upon the skin, or small object or particle found on the person or their clothing, can be interpreted as evidence for the parasitic infestation, and individuals with the condition commonly compulsively gather such "evidence" to present to medical professionals. This presentation is known as the "matchbox sign", "Ziploc bag sign" or "specimen sign", because the "evidence" is frequently presented in a small container, such as a matchbox.[1][4] The matchbox sign is present in five to eight out of every ten people with DP.[1] Related is a "digital specimen sign", in which individuals bring collections of photographs to document their condition.[1]
Similar delusions may be present in close relatives—a shared condition known as a folie à deux—that occurs in 5–15% of cases and is considered a shared psychotic disorder.[4] Because the internet and the media contribute to furthering shared delusions, DP has also been called folie à Internet; when affected people are separated, their symptoms typically subside, but most still require treatment.[4]
Approximately eight out of ten individuals with DP have co-occurring conditions—mainly depression, followed by substance abuse and anxiety; their personal and professional lives are frequently disrupted as they are extremely distressed about their symptoms.[5]
A 2011 Mayo Clinic study of 108 patients failed to find evidence of skin infestation in skin biopsies and patient-provided specimens; the study concluded that the feeling of skin infestation was DP.[1][6]
Cause
The cause of delusional parasitosis is unknown. It may be related to excess dopamine in the brain's striatum, resulting from diminished dopamine transporter (DAT) function, which regulates dopamine reuptake in the brain.[1][4] Evidence supporting the dopamine theory is that medications that inhibit dopamine reuptake (for example cocaine and amphetamines) are known to induce symptoms such as formication. Other conditions that also demonstrate reduced DAT functioning are known to cause secondary DP; these conditions include "schizophrenia, depression, traumatic brain injury, alcoholism, Parkinson's and Huntington's diseases, human immunodeficiency virus infection, and iron deficiency".[4] Further evidence is that antipsychotics improve DP symptoms, which may be because they affect dopamine transmission.[4]
Diagnosis
Delusional parasitosis is diagnosed when the delusion is the only symptom of psychosis, the delusion has lasted a month or longer, behavior is otherwise not markedly odd or impaired, mood disorders—if present at any time—have been comparatively brief, and the delusion cannot be better explained by another medical condition, mental disorder, or the effects of a substance. For diagnosis, the individual must attribute abnormal skin sensations to the belief that they have an infestation, and be convinced that they have an infestation even when evidence shows they do not.[1]
The condition is recognized in two forms: primary and secondary. In primary delusional parasitosis, the delusions are the only manifestation of a psychiatric disorder. Secondary delusional parasitosis occurs when another psychiatric condition, medical illness or substance (medical or recreational) use causes the symptoms; in these cases, the delusion is a symptom of another condition rather than the disorder itself.[2] Secondary forms of DP can be functional (due to mainly psychiatric disorders) or organic (due to other medical illness or organic disease.[4] The secondary organic form may be related to vitamin B12 deficiency, hypothyroidism, anemia, hepatitis, diabetes, HIV/AIDS, syphilis, or use of stimulants like methamphetamine and cocaine.[4][7]
Pruritus and other skin conditions are most commonly caused by mites, but may also be caused by "grocer's itch" from agricultural products, pet-induced dermatitis, caterpillar/moth dermatitis, or exposure to fiberglass. Several drugs, legal or illegal, such as amphetamines, dopamine agonists, opioids, and cocaine may also cause the skin sensations reported. Diseases that must be ruled out in differential diagnosis include hypothyroidism, and kidney or liver disease.[5] 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; some people become fixated on the sensation and its possible meaning, and this fixation may then develop into DP.[8]
Treatment
As of 2019, there have not been any studies that compare available treatments to placebo.[9] The only treatment that provides a cure, and the most effective treatment, is low doses of antipsychotic medication. Cognitive behavioral therapy (CBT) can also be useful. Risperidone is the treatment of choice.[1] For many years, the treatment of choice was pimozide, but it has a higher side effect profile than the newer antipsychotics.[5]Aripiprazole and ziprasidone are effective but have not been well studied for delusional parasitosis. Olanzapine is also effective. All are used at the lowest possible dosage, and increased gradually until symptoms remit.[1]
People with the condition often reject the professional medical diagnosis of delusional parasitosis, and few willingly undergo treatment, despite demonstrable efficacy, making the condition difficult to manage.[1][2][10] Reassuring the individual with DP that there is no evidence of infestation is usually ineffective, as the patient may reject that.[5] Because individuals with DP typically see many physicians with different specialties, and feel a sense of isolation and depression, gaining the patient's trust, and collaborating with other physicians, are key parts of the treatment approach.[4] Dermatologists may have more success introducing the use of medication as a way to alleviate the distress of itching.[4] Directly confronting individuals about delusions is unhelpful because by definition, the delusions are not likely to change; confrontation of beliefs via CBT is accomplished in those who are open to psychotherapy.[5] A five-phase approach to treatment is outlined by Heller et al. (2013) that seeks to establish rapport and trust between physician and patient.[1][11]
Prognosis
The average duration of the condition is about three years.[1] The condition leads to social isolation and affects employment.[1] Cure may be achieved with antipsychotics or by treating underlying psychiatric conditions.[1]
Epidemiology
While a rare disorder, delusional parasitosis is the most common of the hypochondriacal psychoses, and more common than other types of delusions such as those associated with body odor or halitosis.[2] It may be undetected because those who have it do not see a psychiatrist because they don't recognize the condition as a delusion.[2] A population-based study in Olmsted County, Minnesota, found a prevalence of 27 per 100,000 person-years and an incidence of almost 2 cases per 100,000 person-years.[2] The majority of dermatologists will see at least one person with DP during their career.[4]
It is observed twice as often in women than men. The highest incidence occurs in people in their 60s, but there is also a higher occurrence in people in their 30s, associated with substance use.[1] It occurs most often in "socially isolated" women with an average age of 57.[4]
Karl-Axel Ekbom, a Swedish neurologist, first described delusional parasitosis as "pre-senile delusion of infestation" in 1937.[1] The common name has changed many times since then. Ekbom originally used the German word dermatozoenwahn, but other countries used the term Ekbom's syndrome. That term fell out of favor because it also referred to restless legs syndrome (more specifically termed Willis–Ekbom disease (WED) or Wittmaack-Ekbom syndrome).[12][13] Other names that referenced "phobia" were rejected because anxiety disorder was not typical of the symptoms.[13] The eponymous Ekbom's disease was changed to "delusions of parasitosis" in 1946 in the English literature, when researchers J Wilson and H Miller described a series of cases, and to "delusional infestation" in 2009.[1][14] The most common name since 2015 has been "delusional parasitosis".[2]
Ekbom's original was translated to English in 2003; the authors hypothesized that James Harrington (1611–1677) may have been the "first recorded person to suffer from such delusions when he 'began to imagine that his sweat turned to flies, and sometimes to bees and other insects'."[15]
Mary Leitao, the founder of the Morgellons Research Foundation,[16] coined the name Morgellons in 2002, reviving it from a letter written by a physician in the mid-1600s.[17][18] Leitao and others involved in her foundation (who self-identified as having Morgellons) successfully lobbied members of the U.S. Congress and the U.S. Centers for Disease Control and Prevention (CDC) to investigate the condition in 2006.[19][20] The CDC published the results of its multi-year study in January 2012. The study found no underlying infectious condition and few disease organisms were present in people with Morgellons; the fibers found were likely cotton, and the condition was "similar to more commonly recognized conditions such as delusional infestation".[21]
An active online community has supported the notion that Morgellons is an infectious disease, and propose an association with Lyme disease. Publications "largely from a single group of investigators" describe findings of spirochetes, keratin and collagen in skin samples of a small number of individuals; these findings are contradicted by the much larger studies conducted by the CDC.[2]
Society and culture
Jay Traver (1894–1974), a University of Massachusettsentomologist, has been characterized after her death as having made "one of the most remarkable mistakes ever published in a scientific entomological journal",[22] after publishing a 1951 account of what she called a mite infestation.[23] Her detailed description of her own experience with mites was later shown to be incorrect,[22] and has been described by others as a classic case of delusional parasitosis.[24][12][25][26] Matan Shelomi says the paper has done "permanent and lasting damage" to people with delusional parasitosis, "who widely circulate and cite articles such as Traver's and other pseudoscientific or false reports" via the internet, making treatment and cure more difficult.[25] He argues that the historical paper should be retracted because it has misled people about their delusion and that papers "written by or enabling deluded patients", along with internet-fed conspiracies and the related delusion of Morgellons, may increase.[25]
Shelomi published another study in 2013 of what he called scientific misconduct when a 2004 article in the Journal of the New York Entomological Society included what he says is photo manipulation of a matchbox specimen to support the claim that individuals with DP are infested with collembola.[27]
Psychosis is a condition of the mind that results in difficulties determining what is real and what is not real. Symptoms may include delusions and hallucinations, among other features. Additional symptoms are incoherent speech and behavior that is inappropriate for a given situation. There may also be sleep problems, social withdrawal, lack of motivation, and difficulties carrying out daily activities. Psychosis can have serious adverse outcomes.
Scabies is a contagious human skin infestation by the tiny (0.2–0.45 mm) mite Sarcoptes scabiei, variety hominis. The word is from Latin: scabere, lit. 'to scratch'. The most common symptoms are severe itchiness and a pimple-like rash. Occasionally, tiny burrows may appear on the skin. In a first-ever infection, the infected person usually develops symptoms within two to six weeks. During a second infection, symptoms may begin within 24 hours. These symptoms can be present across most of the body or just certain areas such as the wrists, between fingers, or along the waistline. The head may be affected, but this is typically only in young children. The itch is often worse at night. Scratching may cause skin breakdown and an additional bacterial infection in the skin.
Hypochondriasis or hypochondria is a condition in which a person is excessively and unduly worried about having a serious illness. Hypochondria is an old concept whose meaning has repeatedly changed over its lifespan. It has been claimed that this debilitating condition results from an inaccurate perception of the condition of body or mind despite the absence of an actual medical diagnosis. An individual with hypochondriasis is known as a hypochondriac. Hypochondriacs become unduly alarmed about any physical or psychological symptoms they detect, no matter how minor the symptom may be, and are convinced that they have, or are about to be diagnosed with, a serious illness.
Restless legs syndrome (RLS), also known as Willis–Ekbom disease (WED), is generally a long-term disorder that causes a strong urge to move one's legs. There is often an unpleasant feeling in the legs that improves somewhat by moving them. This is often described as aching, tingling, or crawling in nature. Occasionally, arms may also be affected. The feelings generally happen when at rest and therefore can make it hard to sleep. Due to the disturbance in sleep, people with RLS may be sleepy during the day, have low energy, and feel irritable or depressed. Additionally, many have limb twitching during sleep, a condition known as periodic limb movement disorder. RLS is not the same as habitual foot-tapping or leg-rocking.
Delusional disorder, traditionally synonymous with paranoia, is a mental illness in which a person has delusions, but with no accompanying prominent hallucinations, thought disorder, mood disorder, or significant flattening of affect. Delusions are a specific symptom of psychosis. Delusions can be bizarre or non-bizarre in content; non-bizarre delusions are fixed false beliefs that involve situations that could occur in real life, such as being harmed or poisoned. Apart from their delusion or delusions, people with delusional disorder may continue to socialize and function in a normal manner and their behavior does not necessarily generally seem odd. However, the preoccupation with delusional ideas can be disruptive to their overall lives.
Pimozide is an antipsychotic drug of the diphenylbutylpiperidine class. It was discovered at Janssen Pharmaceutica in 1963. It has a high potency compared to chlorpromazine. On a weight basis it is even more potent than haloperidol. It also has special neurologic indications for Tourette syndrome and resistant tics. The side effects include akathisia, tardive dyskinesia, and, more rarely, neuroleptic malignant syndrome and prolongation of the QT interval.
Stimulant psychosis is a mental disorder characterized by psychotic symptoms. It involves and typically occurs following an overdose or several day 'binge' on psychostimulants; however, one study reported occurrences at regularly prescribed doses in approximately 0.1% of individuals within the first several weeks after starting amphetamine or methylphenidate therapy. Methamphetamine psychosis, or long-term effects of stimulant use in the brain, depend upon genetics and may persist for some time.
Rosacea is a long-term skin condition that typically affects the face. It results in redness, pimples, swelling, and small and superficial dilated blood vessels. Often, the nose, cheeks, forehead, and chin are most involved. A red, enlarged nose may occur in severe disease, a condition known as rhinophyma.
Formication is the sensation resembling that of small insects crawling on the skin, in the absence of actual insects. It is one specific form of a set of sensations known as paresthesias, which also include the more common prickling, tingling sensation known as pins and needles. Formication is a well-documented symptom which has numerous possible causes. The word is derived from formica, the Latin word for ant.
False pregnancy is the appearance of clinical or subclinical signs and symptoms associated with pregnancy although the individual is not physically carrying a fetus. The mistaken impression that one is pregnant includes signs and symptoms such as tender breasts with secretions, abdominal growth, delayed menstrual periods, and subjective feelings of a moving fetus. Examination, ultrasound, and pregnancy tests can be used to rule out false pregnancy.
Excoriation disorder, more commonly known as dermatillomania, is a mental disorder on the obsessive–compulsive spectrum that is characterized by the repeated urge or impulse to pick at one's own skin, to the extent that either psychological or physical damage is caused.
Olfactory reference syndrome (ORS) is a psychiatric condition in which there is a persistent false belief and preoccupation with the idea of emitting abnormal body odors which the patient thinks are foul and offensive to other individuals. People with this condition often misinterpret others' behaviors, e.g. sniffing, touching their nose or opening a window, as being referential to an unpleasant body odor which in reality is non-existent and cannot be detected by other people.
The matchbox sign, also referred to as the Ziploc bag sign or the specimen sign, is a psychiatric medical sign in which a patient arrives at a doctor's office with items extracted from the skin; these items are intended to serve as proof of a parasitic infestation, and are typically stored in a small container such as a matchbox. 50–80% of patients with delusional parasitosis present with this sign.
Psychogenic pruritus, also known as psychogenic itch or functional itch disorder is pruritus not associated with a dermatologic or systemic cause. More often than not, it is attributed to a psychiatric cause. Psychogenic pruritus is not the same as neuropathic itch though both are conditions which require more research. This condition is not explained well in DSM-V and is typically considered a diagnosis of exclusion. This condition is not well-studied and it is difficult to ascertain as it is seen by both dermatologists and psychiatrists. In order to provide some consensus to this condition, The French Psychodermatology Group have created diagnostic criteria for this condition.
Morgellons is the informal name of a self-diagnosed, scientifically unsubstantiated skin condition in which individuals have sores that they believe contain fibrous material. Morgellons is not well understood, but the general medical consensus is that it is a form of delusional parasitosis, on the psychiatric spectrum. The sores are typically the result of compulsive scratching, and the fibers, when analysed, are consistently found to have originated from cotton and other textiles.
Gamasoidosis, also known as dermanyssosis, is a frequently unrecognized form of dermatitis, following human infestation with avian mites of the genera Dermanyssus or Ornithonyssus. It is characterized by pruritic erythematous papules, macules and urticaria, with itching and irritation resulting from the saliva the mites secrete while feeding. These bites are commonly found around the neck and areas covered by clothing, but can be found elsewhere on the body. The avian mite Dermanyssus gallinae can also infest various body parts, including the ear canal and scalp.
The International Lyme and Associated Diseases Society is a non-profit advocacy group which advocates for greater acceptance of the controversial and unrecognized diagnosis "chronic Lyme disease". ILADS was formed by advocates for the recognition of "chronic Lyme disease" including physicians, patients and laboratory personnel, and has published alternative treatment guidelines and diagnostic criteria due to the disagreement with mainstream consensus medical views on Lyme disease.
Senile pruritus is one of the most common conditions in the elderly or people over 65 years of age with an emerging itch that may be accompanied with changes in temperature and textural characteristics. In the elderly, xerosis, is the most common cause for an itch due to the degradation of the skin barrier over time. However, the cause of senile pruritus is not clearly known. Diagnosis is based on an elimination criteria during a full body examination that can be done by either a dermatologist or non-dermatologist physician.
Jay R Traver was a University of Massachusetts entomologist who studied and published about mayflies. She described over 200 new species and contributed to the reorganization of the systematics of the entire order. She has been called "the first Ephemeroptera specialist in North America".
↑ Heller MM, Wong JW, Lee ES, etal. (July 2013). "Delusional infestations: clinical presentation, diagnosis and treatment". International Journal of Dermatology (Review). 52 (7): 775–783. doi:10.1111/ijd.12067. PMID23789596. S2CID205187385.
↑ Ekbom KA, Yorston G, Miesch M, Pleasance S, Rubbert S (June 2003). "The pre-senile delusion of infestation". History of Psychiatry (Historical biography). 14 (54 Pt 2): 229–256. doi:10.1177/0957154X030142007. PMID14521159. S2CID444986.
↑ Shelomi M (June 2013). "Evidence of photo manipulation in a delusional parasitosis paper". The Journal of Parasitology. 99 (3): 583–585. doi:10.1645/12-12.1. PMID23198757. S2CID6473251.
Further reading
Halvorson CR (October 2012). "An approach to the evaluation of delusional infestation". Cutis (Review). 90 (4): E1–E4. PMID24005827.
Simpson L, Baier M (August 2009). "Disorder or delusion? Living with Morgellons disease". Journal of Psychosocial Nursing and Mental Health Services (Case report and review). 47 (8): 36–41. doi:10.3928/02793695-20090706-03. PMID19681520.
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