Ekbom Syndrome

Ekbom syndrome, more commonly known by its clinical name delusional parasitosis, is a psychiatric condition in which a person holds a fixed, false belief that they are infested with parasites, insects, worms or other organisms living on or under their skin, despite the absence of any medical evidence of actual infestation. The condition is frequently accompanied by formication, a tactile hallucination of the sensation of insects crawling on or under the skin, which reinforces the underlying belief, and affected individuals often engage in skin picking severe enough to cause real wounds, and commonly collect fragments of skin, lint or debris in containers, a pattern sometimes called the matchbox sign, to present to physicians as physical proof of the supposed infestation. The Swedish neurologist Karl-Axel Ekbom provided an influential detailed clinical description of the condition in 1938, and the syndrome is now generally understood as a form of delusional disorder, somatic type. It can occur as a primary psychiatric condition on its own, or secondary to other causes, including stimulant drug use, other psychiatric illness, or underlying medical conditions that produce genuine sensory disturbances of the skin. When the fixed belief is shared and reinforced between two closely connected people, most often a couple or a parent and child, the resulting shared presentation is classified as folie a deux, a related delusional phenomenon already documented elsewhere in this section.