Hyposmia

Hyposmia, or microsmia,^[1] is a reduced ability to smell and to detect odors. A related condition is anosmia, in which no odors can be detected. Some of the causes of olfaction problems are allergies, nasal polyps, viral infections and head trauma. In 2012 an estimated 9.8 million people aged 40 and older in the United States had hyposmia and an additional 3.4 million had anosmia/severe hyposmia.^[2]

Hyposmia might be a very early sign of Parkinson's disease.^[3] Hyposmia is also an early and almost universal finding in Alzheimer's disease and dementia with Lewy bodies.^[3] Lifelong hyposmia could be caused by Kallmann syndrome^[4] or Autism Spectrum Disorder.^[5] Along with other chemosensory disturbances, hyposmia can be a key indicator of COVID-19.^[6]^[7]

^ Hawkes, Christopher H. (2002). Smell and taste complaints. Boston: Butterworth-Heinemann. pp. 49–50. ISBN 0-7506-7287-0.
^ Hoffman, Howard J.; Rawal, Shristi; Li, Chuan-Ming; Duffy, Valerie B. (10 June 2016). "New chemosensory component in the U.S. National Health and Nutrition Examination Survey (NHANES): first-year results for measured olfactory dysfunction". Reviews in Endocrine and Metabolic Disorders. 17 (2): 221–240. doi:10.1007/s11154-016-9364-1. PMC 5033684. PMID 27287364.
^ ^a ^b Factor, Stewart A., & Weiner, William J., eds. (2008). Parkinson's Disease: Diagnosis and Clinical Management, 2nd ed., pp. 72-73. New York: Demos Medical Publishing.
^ Arkoncel, ML; Arkoncel, FR; Lantion-Ang, FL (March 2011). "A case of Kallmann syndrome". BMJ Case Reports. 2011: bcr0120113727. doi:10.1136/bcr.01.2011.3727. PMC 3070321. PMID 22700069. Kallmann syndrome (KS), a rare genetic disorder, refers to the association between hypogonadotropic hypogonadism and anosmia or hyposmia due to abnormal migration of olfactory axons and gonadotropin-releasing hormone producing neurons.
^ Tonacci, Alessandro; Billeci, Lucia; Tartarisco, Gennaro; Ruta, Liliana; Muratori, Filippo; Pioggia, Giovanni; Gangemi, Sebastiano (2 January 2017). "Olfaction in autism spectrum disorders: A systematic review". Child Neuropsychology. 23 (1): 1–25. doi:10.1080/09297049.2015.1081678. ISSN 0929-7049. PMID 26340690. S2CID 143375600.
^ Lechien JR, Chiesa-Estomba CM, De Siati DR, Horoi M, Le Bon SD, Rodriguez A, et al. (August 2020). "Olfactory and gustatory dysfunctions as a clinical presentation of mild-to-moderate forms of the coronavirus disease (COVID-19): a multicenter European study". European Archives of Oto-Rhino-Laryngology. 277 (8): 2251–2261. doi:10.1007/s00405-020-05965-1. PMC 7134551. PMID 32253535.
^ Xydakis MS, Dehgani-Mobaraki P, Holbrook EH, Geisthoff UW, Bauer C, Hautefort C, et al. (September 2020). "Smell and taste dysfunction in patients with COVID-19". The Lancet. Infectious Diseases. 20 (9): 1015–1016. doi:10.1016/S1473-3099(20)30293-0. PMC 7159875. PMID 32304629.

[1] Hawkes, Christopher H. (2002). Smell and taste complaints. Boston: Butterworth-Heinemann. pp. 49–50. ISBN 0-7506-7287-0.

[2] Hoffman, Howard J.; Rawal, Shristi; Li, Chuan-Ming; Duffy, Valerie B. (10 June 2016). "New chemosensory component in the U.S. National Health and Nutrition Examination Survey (NHANES): first-year results for measured olfactory dysfunction". Reviews in Endocrine and Metabolic Disorders. 17 (2): 221–240. doi:10.1007/s11154-016-9364-1. PMC 5033684. PMID 27287364.

[factor-3] Factor, Stewart A., & Weiner, William J., eds. (2008). Parkinson's Disease: Diagnosis and Clinical Management, 2nd ed., pp. 72-73. New York: Demos Medical Publishing.

[4] Arkoncel, ML; Arkoncel, FR; Lantion-Ang, FL (March 2011). "A case of Kallmann syndrome". BMJ Case Reports. 2011: bcr0120113727. doi:10.1136/bcr.01.2011.3727. PMC 3070321. PMID 22700069. Kallmann syndrome (KS), a rare genetic disorder, refers to the association between hypogonadotropic hypogonadism and anosmia or hyposmia due to abnormal migration of olfactory axons and gonadotropin-releasing hormone producing neurons.

[5] Tonacci, Alessandro; Billeci, Lucia; Tartarisco, Gennaro; Ruta, Liliana; Muratori, Filippo; Pioggia, Giovanni; Gangemi, Sebastiano (2 January 2017). "Olfaction in autism spectrum disorders: A systematic review". Child Neuropsychology. 23 (1): 1–25. doi:10.1080/09297049.2015.1081678. ISSN 0929-7049. PMID 26340690. S2CID 143375600.

[6] Lechien JR, Chiesa-Estomba CM, De Siati DR, Horoi M, Le Bon SD, Rodriguez A, et al. (August 2020). "Olfactory and gustatory dysfunctions as a clinical presentation of mild-to-moderate forms of the coronavirus disease (COVID-19): a multicenter European study". European Archives of Oto-Rhino-Laryngology. 277 (8): 2251–2261. doi:10.1007/s00405-020-05965-1. PMC 7134551. PMID 32253535.

[7] Xydakis MS, Dehgani-Mobaraki P, Holbrook EH, Geisthoff UW, Bauer C, Hautefort C, et al. (September 2020). "Smell and taste dysfunction in patients with COVID-19". The Lancet. Infectious Diseases. 20 (9): 1015–1016. doi:10.1016/S1473-3099(20)30293-0. PMC 7159875. PMID 32304629.

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