Causes

A stuffy nose from a cold is a common cause for a partial, temporary loss of smell. A blockage in the nasal passages caused by a polyp or a nasal fracture also is a common cause. Normal aging can cause a loss of smell too, particularly after age 60.

What is smell?

Your nose and an area in the upper throat have special cells that contain odor receptors. When these receptors detect smells, they send a message to the brain. The brain then identifies the specific smell.

Any problem in this process — a stuffy nose, a blockage, inflammation, nerve damage or a brain function condition — can affect your ability to smell normally.

Problems with the inner lining of your nose

Conditions that cause temporary irritation or congestion inside your nose may include:

• Acute sinusitis (nasal and sinus infection)
• Chronic sinusitis
• Common cold
• Coronavirus disease 2019 (COVID-19)
• Hay fever (allergic rhinitis)
• Influenza (flu)
• Nonallergic rhinitis (chronic congestion or sneezing not related to allergies)
• Smoking

Obstructions of your nasal passages

Conditions or obstructions that block the flow of air through your nose can include:

• Deviated septum
• Nasal polyps
• Tumors

Damage to your brain or nerves

Nerves leading to the area of the brain that detects smell or the brain itself can be damaged or deteriorate due to:

• Aging
• Alzheimer's disease
• Brain aneurysm
• Brain surgery
• Brain tumor
• Diabetes
• Exposure to chemicals in certain insecticides or solvents
• Huntington's disease
• Kallmann's syndrome (a rare genetic condition)
• Klinefelter syndrome (a rare condition in which males have an extra X chromosome in most of their cells)
• Korsakoff's psychosis (a brain disorder caused by the lack of thiamin)
• Lewy body dementia
• Medications (for example, some high blood pressure medications, antibiotics and antihistamines)
• Multiple sclerosis
• Niemann-Pick (Pick's disease, a form of dementia)
• Paget's disease of bone (a disease that affects your bones, sometimes facial ones)
• Parkinson's disease
• Poor nutrition
• Radiation therapy
• Rhinoplasty
• Schizophrenia
• Sjogren's syndrome (an inflammatory disease that generally causes dry mouth and eyes)
• Traumatic brain injury
• Zinc-containing nasal sprays (taken off the market in 2009)
• Zinc deficiency