The authors have no funding, financial relationships, or conflicts of interest to disclose.
Olfactory function in patients with postinfectious and posttraumatic smell disorders before and after treatment with vitamin A: A double-blind, placebo-controlled, randomized clinical trial†
Article first published online: 2 JUL 2012
Copyright © 2012 The American Laryngological, Rhinological, and Otological Society, Inc.
Volume 122, Issue 9, pages 1906–1909, September 2012
How to Cite
Reden, J., Lill, K., Zahnert, T., Haehner, A. and Hummel, T. (2012), Olfactory function in patients with postinfectious and posttraumatic smell disorders before and after treatment with vitamin A: A double-blind, placebo-controlled, randomized clinical trial. The Laryngoscope, 122: 1906–1909. doi: 10.1002/lary.23405
- Issue published online: 23 AUG 2012
- Article first published online: 2 JUL 2012
- Manuscript Accepted: 11 APR 2012
- Manuscript Revised: 20 FEB 2012
- Manuscript Received: 20 DEC 2011
- olfactory loss;
- Level of Evidence: 1b
In this study we investigated the effectiveness of vitamin A in postinfectious and posttraumatic smell disorders. A possible effect of vitamin A is likely due to the stimulation of regeneration and repair of the peripheral olfactory system.
Double-blind, randomized, placebo-controlled clinical trial.
A total of 52 patients (age range, 20–70 years; mean age, 52 years) participated, 26 of whom received placebo (7 male, 19 female) and another 26 verum (8 male, 18 female). A standardized history was obtained in each patient. Olfactory function was measured by means of the Sniffin' Sticks test kit, a validated technique to investigate odor thresholds, odor discrimination, and odor identification. Vitamin A was prescribed at a dose of 10,000 IU per day for 3 months. Follow-up testing was performed on average 5 months after the first investigation.
Forty-four percent of all patients reported recovery of their sense of smell; 29% of the participants exhibited significant improvement in measured olfactory function. However, there was no significant difference between the outcome of patients receiving verum or placebo.
The systemic application of vitamin A at a dose of 10,000 IU per day for 3 months does not appear to be useful in the treatment of postinfectious or posttraumatic olfactory loss.