Effects of systemic or topical administration of corticosteroids and vitamin B in patients with olfactory loss

Background: Aim of the present, unblinded, multicentric, open trial was to compare effects of 3 treatments in patients with olfactory dysfunction. Methods: Treatments included administration of systemic corticosteroids (oral prednisolone), local corticosteroids (mometasone nasal spray), and systemic vitamin B, respectively. A total of 192 patients participated (95 women, 97 men; mean age 56 years). Duration of the smell loss ranged from I to 288 months (average 45 months). Olfactory dysfunction was due to infections of the upper respiratory tract (n = 72), sinunasal disease (n = 19), and posttraumatic olfactory loss (n = 10); the largest portion was classified as idiopathic (n = 85); other causes were rare (n = 6). Results: Following systemic administration of corticosteroids improvement of olfactory function was observed (p<0.001). Similarly, improvement of the sense of smell was found 2 (p = 0.03) and 6 months (p = 0.001) after local administration of mometasone, respectively. In contrast, after administration of vitamin B no significant change of olfactory function was seen after 2 months, while improvement was present after 6 months (p = 0.001). Duration of olfactory dysfunction had no effect on changes of smell function. Conclusions: These results indicate that improvement of olfactory function is found in olfactory dysfunction of different causes. Adequately controlled, blinded studies are needed to further explore potential effects of the various treatments.