Delusional Parasitosis (Morgellons Disease)

Delusional Parasitosis (Ekbom Syndrome, Morgellons Disease) is a psychodermatological disorder^[1] characterized by the recurrent and fixed beliefs they are infested by small organisms or even unanimated materials such as fibres (Morgellons disease), without any objective evidence of infestation/parasitosis.

• Delusional parasitosis may be used interchangeably in the research literature, including Ekbom syndrome, delusory parasitosis, delusional infestation, and Morgellons disease.

• The condition classically presents in middle-aged women of Caucasian descent, and may have underlying psychiatric disorders.

• Patients are typically reluctant to pursue psychiatric consultation and may resist discussing their disease in psychiatric terms. Strategies to strengthen the provider-patient therapeutic alliance facilitate communication around appropriate treatment.
• Without antipsychotic treatment, patients may become heavy utilizers of healthcare and practice self-destructive behaviors in attempts to clear perceived infestations.^[2]

• Substance use disorders, in particular with stimulant or amphetamine misuse, are a risk factor.^[3]

• Delusional parasitosis is not a formal diagnosis in DSM-5, but is most closely related to the diagnosis of delusional disorder, somatic type.

• Morgellons disease (MD) is a more specific form of delusional parasitosis in which affected individuals report embedding of fibres, strands, hairs, or other inanimate materials in the skin. Clinically, patients may presents with multiple non-healing lesions that can be ulcerated and superficially infected.
• Although present in all demographic groups, it is most common in white women who are late middle-aged or older.
  • 77% of MD patients studied in an extensive descriptive study by the Centers for Disease Control (CDC) were female and Caucasian and had a median age of 52 years.^[4]

• Individuals may often collect skin pickings compulsively and display it to medical providers, as proof of their infestation, the “baggie sign.”^[5]

• The etiology of delusional parasitosis can be thought of as being primary (delusional disorder, somatic type), secondary functional (in context of schizophrenia, psychotic depression), or secondary organic (occurring in the context of a medical condition or substance use)
  • Case reports suggest that mixed amphetamine salts, methamphetamine, ephedrine, cathinones, and other substituted amphetamine-type drugs can result in delusional parasitosis.

• True cutaneous infections
  • Diagnosis requires exclusion of organic dermatological etiologies (i.e. - true parasitic cutaneous infections).
• Illness anxiety disorder
  • Delusions of parasitosis could also present in a patient having an underlying illness anxiety disorder, where patients have a preoccupation with disease and need evaluation by practitioners and often need constant support and reassurance.
• Primary psychiatric disorder
  • Delusions of parasitosis may be secondary to various psychiatric illnesses, such as schizophrenia, bipolar disorder, post-traumatic stress disorder, obsessive-compulsive disorder, major depressive disorder, and generalized anxiety disorder.
• Substance use disorder or stimulant/amphetamine use/misuse.
  • It is critical to do a thorough substance use history, in particular for alcohol and stimulant use. Alcohol use, alcohol withdrawal, and amphetamine abuse disorders can also cause secondary delusions of parasitosis.
• Nutritional deficiencies
  • B12 and folate are the two most common vitamin deficiencies that can lead to secondary delusions of parasitosis.
• Neurologic disorders
  • Head trauma, strokes, multiple sclerosis, atrophy, encephalitis, meningitis, and postoperative neurological changes may also result in secondary delusional parasitosis.
• Medication-related
  • Adverse reactions to medications can also cause secondary delusions of parasitosis, including case reports mentioning topiramate, ciprofloxacin, amantadine, steroids, ketoconazole, and phenelzine, which can cause formication symptoms.^[6]

• Although antipsychotic medications are the mainstay of pharmacologic management of MD, other psychotropic medications such as antidepressants may also have utility as adjunct therapies especially if there are underlying mood or anxiety disorders.

• The importance of acknowledging and validating patient distress, adopting a non-confrontational approach, and forming a strong patient–physician relationship is the most critical part of helping patients with delusional parasitosis.
• Frequent, scheduled, regular follow ups are critical to ensure that trust can be fostered.

• Pimozide, a first generation antipsychotic, was historically favoured for management of Morgellons disease due to the early success of the drug in a small RCT in the 1980s.
  • Low-dose pimozide treatment for several months yielded significant improvement to complete resolution of MD lesions.
  • A typical dosing strategy may include starting at pimozide 0.5 mg, and increasing by 0.5 mg every 2-4 weeks. The aim is to increase it to 3 mg per day. Low doses of pimozide or other antipsychotics are thought to lead to decreased sensation of itching and formication as well.
  • Some clinicians suggest remaining on 3 mg until all symptoms disappear and continuing the medication for an additional 3 months before slowly tapering.
  • Some clinicians may not choose pimozide due to the risks of QT interval prolongation, extrapyramidal side effects, drug–drug interactions, and drug-induced depression.
• Second generation antipsychotics such as risperidone, amisulpride, olanzapine, aripiprazole, and quetiapine are considered the drugs of choice for the treatment of MD, and are general thought to have a more favourable side effect profile.

• Some MD patients may feel invalidated or dismissed if the cutaneous manifestations of their condition are overlooked by their physician. Thus, it may be helpful to incorporate certain topical and local therapies (e.g. - antiseptic-containing emollients) into the therapeutic regimen as adjuncts to psychotropic medications.

• MDedge: Treating patients with delusional infestation