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Intranasal vitamin A is beneficial in post-infectious olfactory loss


Vitamin A plays a decisive role in the regeneration of olfactory receptor neurons. In this retrospective study we investigated the effectiveness of topical vitamin A in patients with post-infectious and posttraumatic smell disorders. Retrospective cohort. A total of 170 patients (age range 18–70 years, mean age 52 years) participated. Forty-six patients were treated with smell training only. The remaining 124 patients received smell training and topical vitamin A. Olfactory function was assessed using the Sniffin’ Sticks test kit, a validated technique to measure odor thresholds, discrimination and identification. The duration of olfactory training was 12 weeks. In patients receiving vitamin A, this was applied topically (head back position) at a dose of 10,000 IU/day for 8 weeks. Follow-up testing was performed approximately 10 months after the first assessment. Thirty-seven per cent of all post-infectious patients treated with vitamin A exhibited clinical improvement, whereas only 23% improved in controls. Using a Chi-square test, this was a significant result (χ 2 = 7.06, df = 2, p = 0.03). In addition, when comparing change in score after treatment, olfactory training + vitamin A produced significantly greater improvement compared with training alone, in discrimination score for all patients (1.4 points, p = 0.008), and in threshold and discrimination in the post-infectious group (1.6 points, p = 0.01 and 1.4 points, p = 0.04, respectively). Intranasal vitamin A at a dose of 10,000 IU per day for 2 months may be useful in the treatment of post-infectious olfactory loss. Further work with prospective, placebo-controlled studies is required to confirm these findings.

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We are indebted to Dr. Bettina Hauswald for her help with the clinical examination of the patients.

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Correspondence to Thomas Hummel.

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Thomas Hummel was supported by a grant from the Deutsche Forschungsgemeinschaft (DFG HU441/18-1).

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Hummel, T., Whitcroft, K.L., Rueter, G. et al. Intranasal vitamin A is beneficial in post-infectious olfactory loss. Eur Arch Otorhinolaryngol 274, 2819–2825 (2017).

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  • Olfaction
  • Hyposmia
  • Vitamin A
  • Retinoic acid
  • Therapy
  • Therapeutics
  • Drug therapy
  • Nose