Loss of smell :
Loss of smell(anosmia) is the inability to detect an odor. It may caused by nasal polyps, common cold, influenza, nasal congestion, sinusitis, deviated septum, hay fever, COVID-19, taking antihistamines, smoking, obesity, diabetes, and traumatic brain injury. It may also be caused by conditions that affect nose receptors like Alzheimer's disease, brain tumors, multiple sclerosis, high blood pressure, Kallmann syndrome, Parkinson's disease, Sjogren's syndrome, malnutrition, Klinefelter's syndrome, korsakoff's psychosis, multiple system atrophy, Paget's disease, pick's disease, radiation therapy, rhinoplasty, zinc deficiency, and schizophrenia. Complications of anosmia include food poisoning and an increased risk of inhaling natural gas and harmful chemicals. Diagnosis is made by MRI and CT scan.