Delusional Infestation managed in a combined Tropical Medicine and Psychiatry clinic

Introduction
Delusional infestation is a well-recognised delusional disorder presenting as the persisting belief of the presence of parasitic or other infestations. Combined clinics have been run by dermatology and psychiatry in a small number of centres. Here we report the first few years of a unique combined clinic run with experts in infectious diseases/tropical medicine and psychiatric management of delusional infestation.
Methods
Review of all patients seen at the combined assessment clinics run at LSTM between 19 December 2011 and 31 October 2016. Data were collected prospectively as part of clinical assessment. Descriptive analysis of these data was performed to examine clinical features at assessment, investigations performed and treatment outcomes.
Results
Seventy-five patients were assessed. 52 (69%) were given the formal diagnosis of delusional infestation. 64% of individuals gave a history of travel but no significant tropical or infectious diagnosis was made. 61% of those who returned for follow-up reported improvement in symptoms. The CGI-S improvement was 1.36 for the DI patients, but only 0.63 for non-DI patients. DI patients were more impaired at baseline (5.0 vs 4.1). Health anxiety was the commonest diagnosis seen in those not considered to have DI.
Conclusion
Combined clinics to treat DI are effective in improving patient outcome. A significant minority of patients referred do not have a diagnosis of DI.