Delusional parasitosis

Delusional parasitosis is a mental disorder in which a person holds a persistent false belief that their body is infested with parasites, insects, bacteria or similar organisms, despite there being no actual infestation. Affected people often report tactile hallucinations such as a crawling sensation on or under the skin, called formication, and may pick or scratch at their skin trying to remove the imagined organisms. It is classified in the DSM-5 as a delusional disorder of the somatic subtype. The exact cause is unknown, but it is theorized to involve dysfunctional dopamine transmission in the brain, similar to other psychotic disorders. It is also called Ekbom's syndrome, after the Swedish neurologist Karl-Axel Ekbom, who described it in the late 1930s. The disorder is rare, about twice as common in women as men, with an average age of onset around 57. Most affected people resist treatment because they do not see their belief as false; antipsychotic medication and antidepressants can reduce symptoms.