Hyposmia is a decreased sense of smell, or a decreased ability to detect odors through your nose. Anosmia is the inability to smell anything. These conditions are not very common. The smell is one of our most basic, important senses, and has meaning in our lives when it comes to enjoying a new sensation, remembering past experiences, and even detecting potentially dangerous odors such as smoke or spoiled milk. Loss of smell is a health condition that should be evaluated and treated by an ENT (ear, nose, and throat) specialist, or otolaryngologist.
Symptoms of hyposmia or anosmia may be noticed gradually or suddenly, and include:
Losing the ability to smell can often be accompanied by symptoms of chronic sinusitis, which may include frequent infections, facial pressure and pain, nasal obstruction, and drainage. Decreased sense of smell should not be painful or uncomfortable. Since tasting food and beverages is strongly related to the sense of smell, hyposmia or anosmia may also lead to a decreased desire to eat and drink.
The most common cause of acute or sudden smell loss is nasal blockage. Having inflammation in the nose from a cold, allergies, or an upper respiratory tract infection can cause swelling, which blocks smell particles from reaching the top of the nasal cavity where the smell, or olfactory, nerve is located. It is normal to have decreased or loss of smell during an active cold or sinus infection. However, it is less common to have decreased sense of smell when you’re not feeling ill.
Experiencing hyposmia or anosmia over a long period of time may indicate chronic sinus infection with or without nasal polyps. It may be due to an obstruction in the nose, such as a deviated septum, tissue swelling or, rarely, tumors of the nasal cavity. Nasal trauma can cause a loss of smell, either from a new blockage or from damage to the olfactory nerve. Many cases also occur after a viral infection and can be permanent.
Lastly, people often experience a decrease in their sense of smell as a part of normal aging. This is gradual, usually starting after age 65, but it can be sped up by cigarette smoking or chronic nasal inflammation. If you have decreased sense of smell along with memory loss or difficulty walking, tremors, and speech issues, you should tell your primary care provider about these symptoms right away.
Treatment for hyposmia or anosmia starts with figuring out the cause, so seeing an ENT specialist about these conditions is very important, starting with a thorough medical history and nasal exam. This may include a CT scan or MRI of the nose and sinuses. Specialized smell tests can help determine how much loss of smell you may have experienced.
After looking for the cause, your ENT specialist may decide to treat a nasal inflammation or obstruction. This may involve topical and/or oral medications to reduce inflammation, antibiotics, or surgery inside the nose.
Treatment for permanent loss of smell includes environmental safety recommendations and proper chemical detectors (gas and carbon monoxide) in the home. It also may include nasal rinses, smell retraining therapy, and certain supplements that may be helpful.
Copyright 2021. American Academy of Otolaryngology–Head and Neck Surgery Foundation. Last reviewed April 2020.