This article on Epainassist.com has been reviewed by a medical professional, as well as checked for facts, to assure the readers the best possible accuracy.

We follow a strict editorial policy and we have a zero-tolerance policy regarding any level of plagiarism. Our articles are resourced from reputable online pages. This article may contains scientific references. The numbers in the parentheses (1, 2, 3) are clickable links to peer-reviewed scientific papers.

The feedback link “Was this Article Helpful” on this page can be used to report content that is not accurate, up-to-date or questionable in any manner.

This article does not provide medical advice.


Delusional Infestation : Types, Causes, Symptoms, Diagnosis, Treatment, Prognosis

Delusional infestation, also known as Ekbom syndrome, delusional parasitosis or delusions of parasitosis is an uncommon psychiatric disease where the patient suffering from it has a strong mistaken belief that some kind of parasite is infecting them, when in reality, it is not the case.(1, 2, 3, 4)

A parasite is an organism which thrives on the host, such as spiders, worms, lice, fleas and mites. A person suffering from delusional infestation has uncontrollable thoughts that they have some parasitic infection.

Delusional Infestation : Types, Causes, Symptoms

Types of Delusional Infestation

The three types of delusional infestation are:

  1. Primary Delusional Infestation or Parasitosis: In this the patient suffers from one delusional belief and has only one symptom (monosymptomatic.)(2)
  2. Secondary Delusional Infestation or Parasitosis: In this the patient suffers from other mental health conditions, such as schizophrenia, depression, post-traumatic stress disorder, dementiabipolar disorder and obsessive-compulsive disorder.(2)
  3. Organic Delusional Infestation or Parasitosis: This type of delusional infestation can occur to a person suffering from illnesses, such as diabetes, hypothyroidism, heart problems, menopausecocaine addiction and vitamin B-12 deficiency.(2)

What are the Causes of Delusional Infestation?

The exact cause of delusional infestation is not known. Delusional infestation can commonly occur in middle aged women or older. However, both the genders from any race or age can suffer from this mental health condition.

Sometimes, a person can have delusional parasitosis or delusional infestation as a result of some other disease, which causes chemical imbalance in the brain. This can occur from drug addiction or its use. Experts believe that dopamine, which is a brain chemical, is linked with psychosis.(5)  Any illness or severe stress can cause excess of dopamine in the brain leading to delusional infestation.(6)

What are the Symptoms of Delusional Infestation?

Patients suffering from delusional infestation often consult a dermatologist or any other doctor insisting and convinced that they have a parasite inside their body and that they suffer from a parasitic infection on their skin.(1)

The profound conviction of the patient that they have a parasite within their body is the primary symptom of a patient suffering from delusional infestation or delusional parasitosis. The patient can also be of the belief that their surroundings, home and furniture also is contaminated with parasites.

Another significant symptom of delusional parasitosis or delusional infestation is the crawling sensation which the patient feels on their skin (formication).

Other symptoms of delusional infestation can include:(2)

  • Feeling of numbness.
  • Feelings of burning or itching.
  • Patient will be picking at the skin or scratching the skin.
  • Patient will complain of a prickling or crawling sensation beneath the skin.
  • Presence of ulcers or skin lesions as a result of scratching.
  • Patient can use harsh chemicals to scrub their skin in the hopes of getting rid of the parasite.
  • The patient suffering from delusional infestation can also resort to using adverse home remedies, such as pesticides on their skin.
  • In serious cases of delusional infestation the patient can self-mutilate too.

How is the Diagnosis of Delusional Infestation or Delusional Parasitosis Made?

First a complete physical exam along with blood tests is done to exclude other causes for the patient’s complaints, which include skin numbness, crawling and itching. Some of the conditions, which can produce these symptoms are: thyroid disease; anemia; scabies; kidney disease; HIV infection; having lice; dermatitis herpetiformis; fibromyalgia; Parkinson’s disease; drug/alcohol misuse; Morgellons disease; certain medications and nerve disorders.(3)

How is Delusional Infestation Treated?

Treatment for delusional infestation consists of treating any underlying disease which is triggering this sensation. After delusional infestation has been diagnosed, the patient needs to consult a psychiatrist who will prescribe medications accordingly. Patients suffering from delusional infestation may refuse to take any of these medications, as they are of firm belief that they are suffering from parasitic infection and not a mental health condition.

Talk therapy and family support helps the patient. It is important to consult a psychiatrist, as other doctors won’t be familiar with this disease. The main line of treatment is antipsychotic medications and sometimes antidepressants too.(7) Some of the antipsychotic medications prescribed for treating delusional infestation or delusional parasitosis are: olanzapine, risperidone and aripiprazole.(1, 7)

Sadly, patients suffering from delusional infestation cannot understand the reality of their situation and will not accept that it’s all in their head.

What is the Prognosis of Delusional Infestation?

It takes time and patience to treat delusional infestation and several visits can be needed to the doctor before seeing any improvement. Different medications need to be tried to see which one suits the best and provides relief from the symptoms of delusional infestation, one medication won’t suit all the patients.


Delusional infestation or delusional parasitosis is a rare psychiatric disease, which can be intimidating for the patient as well as family and friends. However, one should persevere and have patience, as with the right treatment and support system the symptoms of this disease can abate and the patient can live a relatively normal life.

There can also be some other underlying disease, which is causing delusional infestation and diagnosis and treatment of this underlying condition will automatically resolve the symptoms of delusional infestation. It can also take time to find the right type of treatment which suits the patient that gives relief from the symptoms.


Team PainAssist
Team PainAssist
Written, Edited or Reviewed By: Team PainAssist, Pain Assist Inc. This article does not provide medical advice. See disclaimer
Last Modified On:September 23, 2022

Recent Posts

Related Posts