Anosmia

Also known as smell blindness, is the loss of the ability to detect one or more smells.
Anosmia may be temporary or permanent. It differs from hyposmia, which is a decreased sensitivity to some or all smells.

When anosmia is caused by inflammatory changes in the nasal passageways, it is treated simply by reducing inflammation.

It can be caused by chronic meningitis and neurosyphilis that would increase intracranial pressure over a long period of time.
Ciliopathy, including ciliopathy due to primary ciliary dyskinesia.

List of causes
Dynamic	Dynamic
Peripheral	Central	Static
Upper respiratory tract infection Sinusitis Common cold COV-19 Hay fever Asthma or allergy	Dementia with Lewy bodies Multiple sclerosis Fibromyalgia Cushing's syndrome Idiopathic hypogonadotropic hypogonadism Primary amoebic meningoencephalitis Parkinson's disease Alzheimer's disease Myasthenia gravis	Nasal polyps Hypothyroidism Head trauma, damage to the ethmoid bone Tumors of the frontal lobe Antibiotics Hypoglycaemia Exposure to hydrogen sulfide (H 2S) by paralysis of the olfactory nerve. Exposure to a chemical that burns the inside of the nose Radiation therapy to the head and neck Chronic atrophic rhinitis Toxins (especially acrylates, methacrylates and cadmium)

Diabetes
Chronic obstructive pulmonary disease (COPD)
Long term alcoholism
Stroke
Epilepsy
Liver or kidney disease
Kallmann syndrome
Primary ciliary dyskinesia
Post-perfusion syndrome
Laryngectomy with permanent tracheostomy
Esthesioneuroblastoma is an exceedingly rare cancerous tumor that originates in or near the olfactory nerve. Symptoms are anosmia (loss of sense of smell) often accompanied by chronic sinusitis.
Intranasal drug use
Aspirin-exacerbated respiratory disease (AERD), also known as Samter's triad
Foster Kennedy syndrome
Cadmium poisoning
Smoking
Neurotropic virus
Schizophrenia
Pernicious anemia
Zinc deficiency
Bell's Palsy or nerve paralysis and damage
Idiopathic intracranial hypertension
Suprasellar meningioma
Refsum's disease
Adrenergic agonists or withdrawal from alpha blockers (vasoconstriction)
Sarcoidosis
Zinc-based intranasal cold products, including remedies labelled as "homeopathic"
Paget's disease of bone
Cerebral aneurysm
Granulomatosis with polyangiitis
Snakebite
Idiopathic anosmia (cause cannot be determined)

COV-19
HSV-1, HSV-2 </ref> Landis BN, Vodicka J, Hummel T. Olfactory dysfunction following herpetic meningoencephalitis. J Neurol. 2010 Mar;257(3):439-43. doi: 10.1007/s00415-009-5344-7. Epub 2009 Oct 10. PMID: 19820982.</ref>
NVCJD (Ref: REUBER M, AL-DIN ASN, BABORIE A, et al, New variant Creutzfeldt-Jakob disease presenting with loss of taste and smell, Journal of Neurology, Neurosurgery & Psychiatry 2001;71:412-413.
CJD (Ref: Sporadic CJD Found in Olfactory Cilia, Medscape)

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Notes