Anosmia is the lack of sense of smell and frequently goes hand in hand with the lack of taste. Since the smell receptors are in the upper portion of the nose, anything that can prevent air from reaching these smell receptors can affect your ability to smell. The receptors are located on both sides of the nose, so complete blockage of both your nasal passages may lead to loss of smell, but blockage of one side or the other can also cause this in some people.
Usually, when your nasal breathing improves, so does your sense of smell. Although congestion and obstruction are often the cause of smell issues, there are several other reasons not related to nasal obstruction why people can lose their sense of smell, including recent or repetitive head injury, a viral cold, COVID-19 infections, and many others including chronic nasal and sinus conditions, such as polyps.
COVID-19—The loss of smell, with or without changes in taste, related to COVID-19 infection typically occurs without the nasal congestion or runny nose that is typically seen with a cold. Associated symptoms may also include headache, a dry cough, shortness of breath, high fever, stomach problems, and a persistent sore throat. More severe symptoms such as these often point to COVID-19 or the flu. During the pandemic, anyone who has a new loss of smell or taste, even without any of those other symptoms, should be suspected of having COVID-19 and be tested, whether or not they have been previously vaccinated. Polymerase chain reaction (PCR) testing for COVID-19 can be easily obtained and will identify those patients with COVID-19.
Patients that experience a loss of smell from COVID-19 that does not get better after several months may benefit from, smell retraining therapy. This treatment, which can be done at home by sniffing four different scents twice a day for four to six months, has proven to improve the smell for some, but not all patients. An ENT specialist may advise additional therapies, such as sinus rinses with topical nasal steroids. Parosmia, or altered sense of smell, may occur weeks or months after loss of smell with COVID-19.
URI (Upper Respiratory Infection)—Nasal obstruction and thick nasal drainage with or without the loss of smell commonly occur with a cold (viral URI). These self-confined symptoms are usually limited to the nasal and sinus areas and most times go away in five to seven days. These URIs are often associated with a mild fever. Initial treatment of URIs often benefits from symptomatic care alone without the need for an antibiotic, and they usually clear without the need for a physician visit. If the symptoms do not go away or get worse after five to seven days, a physician visit might be needed. Occasionally, a viral URI will have a lingering effect on your sense of smell, and you should see an ENT (ear, nose, and throat) specialist, or otolaryngologist, for further evaluation if it persists after your nasal breathing returns to normal.
Allergic Rhinitis—Environmental allergies can result in acute or chronic symptoms that can be mistaken for a viral URI or sinus issues. Depending on where you live, allergic rhinitis is usually seasonal. Allergic patients have a clear nasal discharge and nasal congestion with post-nasal drainage or drip as well as runny eyes, sneezing, and itching. Some patients will only experience congestion or obstruction.
Over the counter (OTC) allergy medications or prescription medications that your primary care physician provides usually control the symptoms well. Those who are still suffering from allergies after trying medications can benefit from an evaluation by an ENT specialist to identify your allergies and other related problems that prevent improvement. They will be able to offer additional medical treatments, drops, or shots.
Acute Rhinosinusitis (commonly known as Acute Sinusitis)—Although less common, an URI, bad dental infection of the upper teeth, or severe allergy disease can lead to acute bacterial sinusitis. Symptoms include nasal congestion, which can lead to changes in smell and taste, facial pain and pressure, fever, foul nasal discharge, and occasionally swelling. It often hurts to just touch your face. Antibiotics are sometimes needed and can be obtained from your primary care physician or an ENT specialist.
Many healthy people can get well from acute bacterial rhinosinusitis without antibiotics using supportive therapy such as saltwater rinsing. If the sinus infection is caused by tooth infections, then they often improve when the tooth infection is addressed by your dentist. If not, the patient should see an ENT specialist for further treatment.
Chronic Rhinosinusitis (commonly known as Chronic Sinusitis or CRS)—Once sinus infections last more than three months, they are considered “chronic.” Patients with chronic rhinosinusitis usually complain of nasal blockage and thick nasal drainage with or without loss of smell, facial pain or tenderness and sometimes headaches. Chronic rhinosinusitis can occur with or without nasal polyps, and the presence of polyps often will require more individualized care An evaluation by an ENT specialist is recommended for proper diagnosis and treatment.
In any of these situations mentioned above, if OTC treatments do not provide rapid improvement in symptoms, seeing an ENT specialist can help differentiate between the various conditions that may be causing smell loss.
Your age as well as how long you have had symptoms of smell loss before seeking treatment, no matter what the cause, are the two main factors affecting your ability to regain your sense of smell. Therefore, if your smell does not return quickly, you should see an ENT specialist as soon as possible.
For those with loss of smell, there are safety concerns that should be considered, such as making sure all smoke detectors are working properly; installing natural gas or propane leak alarms (these are different from carbon monoxide detectors) if there are gas appliances, fireplaces, furnaces, or water heaters in the home; and checking food expiration dates.