Delusional disorder, somatic type: olfactory reference syndrome in a patient with delusional trimethylaminuria.

Delusions of foul body odors (often referred to as olfactory reference syndrome [ORS]) currently fall under the category of delusional disorder, somatic type (DDST), in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). We present the case of a 51-year-old man with no previous psychiatric history who presented with perceived foul odors that he delusionally attributed to trimethylaminuria (TMAU). TMAU is a rare metabolic disorder associated with foul body odors. The patient also experienced severe concurrent mood symptoms because of social isolation resulting from his delusion about his body odors. After considerable discussion of differential diagnoses, a diagnosis of DDST was ultimately made, given the patient's unrelenting nonbizarre delusions and lack of insight pertaining to his body odors. However, this case proved to be very useful in exploring the diagnostic challenges in this type of disorder and recent discussions of ORS and its proposed inclusion in the DSM-5.