Variable Clinical Presentations of Secondary Delusional Infestation: An Experience of Six Cases from a Psychodermatology Clinic

Abstract

Delusional Infestation (DI) is a relatively rare condition with a fixed belief of being infested with living organisms, despite a lack of medical evidence of such infestation. Although it seems to be a psychiatric disease, patients commonly are admitted to dermatology clinics because of skin findings. Psychiatrists can underestimate its prevalance, whereas dermatologists can miss the diagnosis. It should be managed as a psychodermatological disease. Our aim in the study was to evaluate six patients with different clinical presentations of DI and to emphasize some clinical features. All patients were internalized in the psychodermatology clinic for this study. Medical history and clinical data from dermatologic and psychiatric examinations were noted; Mini International Neuropsychiatric Interview (MINI-Plus) and laboratory investigations including blood and urine analyses, microscopic analysis of so-called pathogens, and skin biopsy if needed, were performed. The diagnosis was made based on detailed history, dermatologic and psychiatric examinations, and laboratory investigations. All patients had symptoms of itching, burning, or crawling sensations dermatologically and thus were admitted to dermatology clinic. They were all considered secondary DI to another medical condition or to psychiatric illness. Vitamin B12 deficiency, diabetes, and hypothyroidism were the underlying medical conditions. Related psychiatric illnesses were trichotillomania and schizoaffective disorder, schizophrenia, shared pychotic disorder, and brief psychotic disorder. Two patients had delusions of inanimate materials; four patients had partial and complete remissions; and two patients have dropped out. Each patient had different clinical characteristics creating diagnostic challenges. All complaints were related to the infestation of the skin. The presence of different psychiatric comorbidities is remarkable. It seems that both psychiatrists and dermatologists can face diagnostic and therapeutic challenges of this complex disease in clinical settings, particularly if there are unusual clinical features of DI. Therefore, both psychiatrists and dermatologists should be well aware of DI.