Patterns of non-conductive olfactory disorders in eastern Austria: a study of 120 patients from the Department of Otorhinolaryngology at the University of Vienna

BACKGROUND: About 1% of the population suffer from disorders of the chemosensory system. In the United States at least two million people have problems related to smell and taste. The sense of smell enables the individual to determine the flavour of food and beverages and is most important as a sophisticated warning system. For the present investigation, we collected data on the age pattern and causes of olfactory disorders in eastern Austria. METHODS: 120 patients with non-conductive olfactory disorders were examined over a 9-month period starting from July 1998 at the outpatient clinic of the Ear Nose and Throat Department of the University of Vienna. Data concerning the underlying population taken from the 1998 population census in Vienna were used for comparison, in order to gain a more representative estimation of the distribution of these disorders. The diagnosis was based on thorough history taking, physical examination, CT scan, and olfactory testing for sensitivity by means of so-called "sniffin' sticks". RESULTS: The patients' ages ranged from 16 to 86 years (mean, 54.5 years; 74 females, 46 males). Those older than 50 years seem to have a higher risk of developing olfactory disorders. Only 15 of the female patients were pre-menopausal. Olfactory disorders were most frequently caused by viral infections in the upper respiratory tract (n = 51). Fifteen patients reported head trauma as a cause of olfactory loss, and 45 causes were idiopathic. Most of those in whom the olfactory disorder had been in existence for less than 3 months were anosmic (84%), very few were hyposmic (16% of a total of 19 patients). In contrast, 38% (of a total of 29 patients) in whom the disease had been in existence for 3 and 6 months were hyposmic. Parosmia was reported in 16 cases. Most parosmias appeared after viral infection (56%). Eight of the 120 patients reported dysgeusia. CONCLUSIONS: The present study is a first step towards an assessment of olfactory disorders in Austria. We found similar causes of non-conductive olfactory disorders as have been reported in the literature for other countries, namely upper respiratory infection leading to postviral olfactory disorders, and head trauma. With increasing age women seem to suffer more often from chemosensory dysfunction than men, which may be related to hormonal factors.