Nosographic considerations on delusional parasitosis based on three clinical observations

Ekbom syndrome or delusional parasitosis is a rare disease characterized by the unwavering conviction of having cutaneous infestation of insects or parasites. This is a monothematic delusion of hallucinatory origin that typically affects older women. We report the case of three patients with delusional parasitosis in different clinical settings. The first patient suffered from isolated delusional parasitosis corresponding to the condition described by Karl Ekbom. The second case suffered from secondary delusional parasitosis, occurring in the setting of leukoencephalopathy (CADASIL). Lastly, the third patient appeared in a state which was evocative of a depressive episode with psychotic symptom integrating delusional parasitosis. These three clinical vignettes perfectly illustrate the trans-nosographic dimension of this syndrome and the difficulties in treating these patients, both in terms of therapeutic alliance and of choice of pharmacological treatment.