If​ you suddenly experience the loss of taste and smell, your first reaction is probably concern about COVID-19. You may be surprised (and perhaps relieved) to find out there are other disorders that can cause those symptoms as well.
Let's consider some of the symptoms that are indicating the problem:-
Symptom 1
You're suffering from severe hay fever with a runny, itchy nose; your eyes are swollen and watering. Your sense of smell is also blunted.
It could be
Hay fever causes a loss of smell. Your nose contains odour receptors, which send messages to the brain via nerves when they detect smells. The brain then identifies the specific odour. With hay fever, these receptors are temporarily damaged.
Cure it
Use eye drops and a nasal spray to control your symptoms. Keep car and house windows closed. Put Vaseline into your nostrils to prevent pollen from entering.
Symptom 2
You had Covid six weeks ago when your mouth tasted disgusting and your sense of smell disappeared. Your sense of taste is normal now, but not your ability to smell.
It could be
The Covid virus has attacked the odour receptors in your nose and damaged them. They may or may not recover.
Cure it
Loss of sense of smell could be a part of long Covid, the aftermath of the Covid infection, which can take months to recover from.
Symptom 3
You play football on weekends and recently fell and broke your nose. Since then, you've lost your sense of smell. The swelling has subsided but your sense of smell hasn't returned.
It could be
Damage to the nerves in the nose which carry odour messages to the brain. Your smell may gradually return, but it may not.
Cure it
Hot and cold compresses can help the swelling. Blow your nose gently. See an ENT surgeon for reconstruction surgery and straightening out the nasal septum.