Delusional parasitosis, also known as Ekbom syndrome, is the most frequent among the somatic delusions. It may occur at any age but is more common in the elderly, particularly in females. It is a syndrome in which the patient has the false belief that he is infested by some type of insects, lice, worms or other invertebrates, and that they live or grow under their skin or inside their body. Psychiatric interventions are usually rejected by these patients and long-term treatments are frequently abandoned.

A clinical case was followed and reviewed to illustrate the links between somatic delusions, hypochondriasis, somatization and obsessive disorders.

A 58-year-old female presents delusions of infestation. She has a long history of somatization and hypochondria, which can be interpreted as a continuum in the onset of the delusional syndrome. In this case, delusions of infestation are projected onto a third person. Psychophramacological treatment with long acting injectable risperidone was then introduced, as an alternative to drugs previously used.

The effectiveness of pimozide and risperidone for the Ekbom syndrome has been documented in the literature. In our case, we decided to introduce long acting injectable risperidone after several rejections or long-term discontinuation in oral treatments.