title: 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.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  Double-blind, randomized, placebo-controlled clinical trial.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors: Department of Otorhinolaryngology, University of Dresden Medical School, Dresden, Germany. jens.reden@uniklinikum-dresden.de
authors: Jens
authors: J
authors: Reden
authors: Katja
authors: K
authors: Lill
authors: Thomas
authors: T
authors: Zahnert
authors: Antje
authors: A
authors: Haehner
authors: Thomas
authors: T
authors: Hummel
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009666:Nose / Q000293:injuries*; D000857:Olfaction Disorders / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology; D009832:Olfactory Nerve / Q000503:physiopathology*; D012016:Reference Values; D012220:Rhinitis / Q000150:complications / Q000175:diagnosis; D012720:Severity of Illness Index; D012903:Smell / Q000187:drug effects*; D016896:Treatment Outcome; D014801:Vitamin A / Q000627:therapeutic use*; D014947:Wounds and Injuries / Q000150:complications; D055815:Young Adult
chemical_list: D014801:Vitamin A