An epidemiological study of postviral olfactory disorder

Postviral olfactory disorder develops after infection with the common cold, and is a relatively severe and prolonged disorder without rhino-sinusitis. This epidemiological study aimed to characterize its clinical pathology an d determine the causative virus. Postviral olfactory disorder occurs most c ommonly in middle-aged women and is most prevalent in spring and summer. A comparison of the monthly frequency of the disorder with thr incidence of i solation of various viruses suggest that the influenza virus, respiratory s yncytial virus, and herpes virus are not causative viruses, while parainflu enza virus type 3 is most likely to he a causative virus. This conclusion i s supported by immunological study and analysis of symptoms of the cold. Al l patients with postviral olfactory disorder had increased serum antibody t itre for parainfluenza virus type 3. No prominent or specific symptoms of c ommon cold were identified as a potential trigger of this syndrome in patie nt questionnaires.