Last reviewed: 8 Apr 2021
Last updated: 28 Jul 2020




  • Dental (periodontal) disease
  • Upper respiratory tract infection
  • Antimicrobial/antihypertensive therapy
  • Chemotherapy/radiotherapy to the head and neck
  • Dental procedure-related trauma
  • Tonsillectomy
  • Middle ear surgery
  • Bell's palsy
  • Medication-related
  • Burning mouth syndrome


  • Chronic middle ear infections
  • Coronavirus disease 2019 (COVID-19)
  • Upper airway endoscopy
  • Oral surgical procedures
  • Skull base surgery
  • Ramsay Hunt's syndrome
  • Stroke
  • Head trauma
  • Parkinson's disease
  • Alzheimer's dementia
  • Amyotrophic lateral sclerosis
  • Multiple sclerosis
  • Epilepsy
  • Myasthenia gravis
  • Guillain-Barre syndrome
  • Sjogren syndrome
  • Renal insufficiency
  • Liver failure
  • Diabetes mellitus
  • Hypothyroidism
  • Pontocerebellar angle tumours
  • Paraneoplastic syndrome
  • Iron deficiency
  • Vitamin B12 deficiency
  • Zinc deficiency


Associate Professor

Weill Cornell Medical College

Division of Oncology

New York



AB declares that he has no competing interests.

Consulting Staff

Director of Oral Health Services

Division of Head and Neck Surgery

Professor of Oral Medicine

Department of Surgery

City of Hope


Los Angeles



JE declares that he has no competing interests.

Dr Andrei Barasch and Dr Joel Epstein would like to gratefully acknowledge Dr Stéphanie Collet, Dr Basile Nicolas Landis, and Dr Philippe Rombaux, previous contributors to this topic. SC is an author of a reference cited in this topic. BNL has been reimbursed for speaking on olfactory disorders at a neuroscience meeting in Switzerland and is an author of a number of references cited in this topic. PR is an author of a number of references cited in this topic.

Peer reviewersVIEW ALL

ENT Specialist

Department of Otorhinolaryngology

University of Dresden Medical School




VG declares that he has no competing interests.

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