Delusions of Parasitosis

Key Points
Psychological in nature
Person believes he or she is infected with parasites
Also known as Ekbom’s Syndrome

Delusions of parasitosis is a delusional disorder wherein the victim has a fixed belief that he or she is infected with parasites, though no such parasites exist. The victims imagine that bugs are crawling under the skin.

There are three types of delusions of parasitosis:

1) Primary: The victims delusions are limited only to belief that he or she has bugs under the skin
2) Secondary: The victim is suffering from other forms of psychosis like schizophrenia or depression, and parasitosis is associated with those delusions.
3) Secondary Organic: The delusions are triggered by drug use or a medical illness, such as cancer, Tuberculosis, or diabetes.

Differential Diagnosis (Other conditions with similar appearance)

Dermatitis Herpetiformis
Scabies

Diagnosis
Usually made by clinical assessment, and scrapings of the skin can also provide a diagnosis

Symptoms of Delusions of Parasitosis vary among sufferers, but the belief that bugs are burrowing under the skin is common to most sufferers. In many cases the patients have another underlying psychiatric disorder such as anxiety or depression. In such a setting, typical harmless skin symptoms, such as itching from dryness, are misinterpreted by the brain as a sign of infestation. Once the fixed false belief is established, it is very difficult for the patient to come to terms with the real problem. Itching is a common complaint, and secondary infection from scratching is often seen. Doctors may also test for the use of illicit drugs, like cocaine, which can trigger the sensations of bugs crawling under the skin.

Treatment
Anti-psychotic medications
Difficult to treat because patients deny the delusions

Treatment is very challenging. Often patients will refuse treatment, believing that the provider is mistaken regarding the diagnosis. Any underlying anxiety and/or depression must be addressed and treated. Anti-psychotic medications, such as Pimozide, Olanzapine or Risperidone can also be attempted. If the delusions are triggered by illicit drug use, the drug use should be discontinued. In many cases, referral to a psychiatrist should be considered.