You rely on your nose to allow you to enjoy the smell of food, the scent of fresh flowers in the meadow, and the noxious odors that indicate food has gone off. When you realize your sense of smell is fading, you're bound to experience mixed emotions -- one of which is sure to be worry. What's causing your sense of smell to fade? Here's a look at the possibilities.

Nasal Polyps

This is the most likely cause of a loss of smell, which is good news since nasal polyps are a rather minor and treatable problem. Nasal polyps are growths that appear in the nose cavity and sinuses. They're not cancerous, but their presence reduces the amount of air flow into the sinuses. They may also press on nerves, impeding your sense of smell. If you have also had trouble breathing through your nose, nasal polyps are the most likely explanation for a loss of the sense of smell. Visit an ear, nose, and throat doctor for an evaluation. If polyps are to blame, they can generally remove them quite easily.

Medications

Did you just start taking a new medication? Look closely at the label, and you may find that a loss of the sense of smell is a side effect. (It may be listed as "anosmia" as this is the technical term for your symptom.) Antidepressants, antibiotics, and anti-inflammatory medications commonly have this side effect. If the medication is something you've been prescribed temporarily, like an antibiotic for a UTI, then you might just want to deal with the anosmia until your course of medication is complete. If it's a medication you're supposed to take longer-term, talk to your doctor. See if they can adjust your dose or give you a different, yet similar medication that won't cause the same side effects.

Brain Tumor

A brain tumor is not a common cause of anosmia, but it is one you should consider -- especially if you're pretty sure medications and nasal polyps are not to blame. The tumor could be growing in such a place that it presses on neurons related to your sense of smell. If you have also noticed any headaches, excessive tiredness, or tremors, these could also indicate a brain tumor or other neurological condition. Make an appointment with a neurologist; they can administer a few tests to diagnose you. The sooner you detect and treat the problem, the better the outcome.