What Is Delusional Parasitosis?

Delusional parasitosis, also known as Ekbom syndrome, is a rare psychiatric disorder that causes people to falsely believe they are infected with bacteria, parasites, worms, and other small organisms. There are about 1.9–27.3 cases per 100,000 people per year.

Some people develop delusional parasitosis of their own. Others have delusions as a result of an underlying health problem or mental illness. You might feel like you have a parasite on or inside your skin. You'll frequently visit healthcare providers about your concerns despite test results showing that you do not have a parasite. Treatment includes antidepressant and antipsychotic medications and talk therapy.

Delusional parasitosis can be a confusing and frustrating process, Thea Gallagher, PsyD, a clinical assistant professor of psychology at the NYU Grossman School of Medicine, told Health. Read on to learn about delusional parasitosis, including symptoms, causes, treatment, and more.

Types of Delusional Parasitosis

Delusional parasitosis is a rare psychiatric disorder that causes delusions of being infected with a parasite or other small organisms, such as bacteria, fungi, and worms. This psychiatric disorder may happen on its own or as a result of a health condition, medication use, or substance abuse disorder. There are two types of delusional parasitosis: primary and secondary.

Primary

This type causes delusional parasitosis symptoms without a known cause. People with primary delusional parasitosis typically do not have a history of mental health conditions.

Secondary

This type occurs with other health concerns, including a thyroid disorder and diabetes, or another mental illness. For example, paranoid delusions might be a sign of psychosis or schizophrenia. Psychosis is a disconnection from reality. Schizophrenia is a brain disorder that causes delusions, difficulty thinking, and hallucinations.

"If someone is presenting with these symptoms, [it may be] an indication that they are struggling with a severe and persistent mental illness," said Gallagher.

Secondary delusional parasitosis might occur with substance abuse disorder. Some people develop delusional parasitosis as a side effect of medications like amantadine, ciprofloxacin, and steroids.

Delusional Parasitosis Symptoms

"Individuals will often have this sensation that they have some sort of parasitic infection," Keith Stowell, MD, chief medical officer for Rutgers University Behavioral Health Care, told Health. "It can feel like something has crawled under their skin or is embedded in their hair. It manifests in different ways."

According to Dr. Stowell, delusional parasitosis causes mental and physical symptoms like:

• A feeling like you have a parasite on or inside your skin
• Brain fog
• Damaging or removing part of your skin or applying toxic items to your skin to get rid of the parasite
• Gastrointestinal (GI) symptoms (e.g., constipation and diarrhea)
• Fatigue
• Morgellons syndrome, which causes you to see fibers coming out from your skin
• Pain
• Taking samples of your hair, lint, or skin to a healthcare provider to "prove" you have an infection despite test results showing otherwise

"People actually feel like they have itchiness, pain, or like something is crawling on or under their skin," said Dr. Stowell. Those symptoms might result in emotional distress and skin irritation.

What Causes Delusional Parasitosis?

There's still a lot that researchers do not know about delusional parasitosis: "There are a relatively sparse number of cases," said Dr. Stowell.

Still, some evidence suggests that weak striatal dopamine transporters (DATs) might cause primary and secondary parasitosis. DATs regulate the signaling of dopamine, a neurotransmitter in your brain that controls functions like attention, memory, and mood.

Risk Factors

Some people develop delusional parasitosis on its own. Others develop symptoms as a complication of a health problem, medication, mental illness, or substance use. Research has shown that certain factors affect dopamine signaling, which might cause delusional parasitosis.

Risk factors include:

• A thyroid disorder
• Certain medications (e.g., amantadine, ciprofloxacin, and steroids)
• Diabetes
• Neurological conditions (e.g., dementia and stroke)
• Nutrient deficiencies (e.g., folate and vitamin B12)
• Some infectious diseases (e.g., HIV, leprosy, syphilis, and tuberculosis)
• Substance use disorder

Furthermore, older age may be an independent risk factor for delusional parasitosis, as the condition is commonly observed in people assigned female at birth who are over 50 years old.

How Is Delusional Parasitosis Diagnosed?

People with delusional parasitosis believe they are infected with a parasite, so they'll usually seek a diagnosis. Still, it's possible that you might have an infection. Healthcare providers will generally do an initial workup to see if they can find a parasite, said Dr. Stowell. They'll send you home if your test results are negative.

Diagnostic tests you might receive to help rule out a parasitic infection:

• Colonoscopy: This checks your large intestine for signs of a parasite.
• Imaging: These tests, such as a CT scan and X-ray, take detailed pictures of the inside of your body.
• Lab tests: A healthcare provider might obtain a complete blood count (CBC). They will look for a high level of eosinophils, or white blood cells. Increased eosinophils indicate a parasitic infection.
• Skin biopsy: People often report itching or feeling like something's moving in their skin. They may first go to a dermatologist after scratching or picking the affected area. A healthcare provider might take samples of your skin to check for a parasite.

Only when you keep coming back and insisting you have a parasite will a healthcare provider consider delusional parasitosis. They will typically try to bring in a mental healthcare provider to make an actual diagnosis.

Treatments for Delusional Parasitosis

Delusional parasitosis can be tricky to treat: "A lot of individuals do not view this as a psychiatric issue, so they're unwilling to accept psychiatric treatment for it," said Dr. Stowell. One of the main goals of treatment is to build a trusting relationship with a healthcare provider.

Treatments include:

• Antidepressants: Selective serotonin reuptake inhibitors (SSRIs) help relieve depression symptoms that might be the cause of delusional parasitosis.
• Antipsychotics: A healthcare provider may prescribe a low-dose antipsychotic medication, such as aripiprazole, olanzapine, or risperidone if you are willing.
• Cognitive behavioral therapy (CBT): This form of talk therapy aims to change how you view a situation or stressor. CBT may help "restructure" your delusions.
• Electroconvulsive therapy (ECT): This is shock therapy that sends an electric current through your brain to relieve severe symptoms.

How To Prevent Delusional Parasitosis

You might be able to prevent delusional parasitosis by treating underlying health problems and mental illnesses. The psychiatric disorder is often a complication of severe mental illnesses, such as schizophrenia. It's essential to work with a mental healthcare provider to treat symptoms.

Healthcare providers might help prevent delusional parasitosis by reassuring people and taking their symptoms seriously. Compassion avoids angering or insulting someone with delusional parasitosis. A strong relationship with a healthcare provider helps build trust and treat symptoms easily.

Complications

Delusional parasitosis might result in a few complications, especially if untreated, such as:

• Decreased function: The fear of having a parasitic infection may severely impact your life and interfere with your school, work, and other daily activities.
• Keratoconjunctivitis: This causes inflammation of your conjunctiva (the membrane that covers your eye) and cornea (the clear outer layer in the front of your eye). Attempting to get rid of a parasite might bring about this eye disease.
• Skin concerns: Some develop scarring by scratching, trying to collect samples, and ridding their bodies of a parasite.

A Quick Review

Delusional parasitosis is a rare psychiatric disorder that causes delusions of being infected with a parasite or other small organism. Some people develop delusional parasitosis as a result of another mental illness or health problem, such as a thyroid disorder or substance use disorder.

You might consider seeing a mental healthcare provider if you frequently have concerns about having a parasite despite negative test results. Treatment typically includes antidepressant and antipsychotic medications and talk therapy.