Loss of smell

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at December 2, 2015
StartSymptomsLoss of smell

A healthy sense of smell not only makes life more enjoyable, it also warns against danger and can be an important barometer of overall health. The loss of a sense of smell can be partial or complete, and has many causes. And while losing the ability to smell is rarely a serious condition in itself, it can have a significant impact on daily life. Because the loss of smell results from medical conditions as well as injuries to the nose or brain, preventing and treating it can take many forms ranging from simple lifestyle changes to interventions such as surgery.


Definition & Facts

The sense of smell is one of the most basic of senses, a primal feature that alerts to danger as well as good food and other pleasures. Although the sense of smell is still not well understood, it depends on a chain of neurological connections that start with scent receptors in the nose.

When activated, these receptors send signals via the olfactory nerve to the brain. The sense of smell is not restricted to simply identifying odors. Smells are also connected to taste, memory and mood, as the olfactory response triggers activity in these areas of the brain as well. Recent studies have also indicated a connection between a declining sense of smell and Alzheimer’s disease.


The sense of smell can be lost for many reasons. In some cases the sense of smell is reduced but not lost entirely, a conditon called hyposmia. In other cases the loss of smell is complete, known as anosmia. The sense of smell can also be distorted, so that the sufferer perceives odors differently, a condition called dysosmia in which normally pleasant odors smell foul, and vice versa.

It may be temporary, such as when a cold, allergy or sinus infection creates mucus that stuffs the nose. Polyps in the nasal passages can also block the sense of smell. Injuries to the nose and nasal passages can also damage smell receptors. Aging, too, plays a role, as most people experience at least some decline in the senses as they get older. A variety of diseases can also contribute to a loss of smell, such as Parkinson’s disease, Multiple sclerosis, and Sjogren’s syndrome.

Damage to the brain resulting from injury, surgery or events such as strokes or aneurysms can also result in a loss of smell, and so can exposure to environmental toxins, radiation and even certain medications. Malnutrition and vitamin deficiencies can also play a role. Even rhinoplasty – plastic surgery on the nose – can cause a loss of smell. The loss of smell can be either partial or total, and is rarely life threatening in itself. Many cases of smell loss can be reversed with treatment of the underlying causes. Even smoking can cause a loss of smell.

When to see a doctor

Loss of smell from minor causes such as allergies, colds and flu, or sinus problems usually clears up on its own. But if the condition occurs suddenly, persists or worsens, medical experts suggest seeing a doctor to track down the root cause of the problem. Since loss of smell can result from many causes such as diseases, brain problems blockages in the nasal passages, or even nutritional deficiencies, it’s important to address these conditions to treat or restore the sense of smell.

Treatment & Therapy

Treatment of smell loss or decline depends on the cause. If the loss of smell results from an injury to the nose, or a blockage in the nasal passages such as polyps, surgery to remove the obstructions may solve the problem. Sinus infections can be treated with antibiotics. Smell loss from vitamin deficiencies and malnutrition can be treated with supplementation and improvements in diet to increase the intake of essential vitamins and minerals such as zinc and thiamin.

If the condition is a result of an underlying disease state such as Parkinson’s, treating the disease itself may help restore the sense of smell. Lifestyle changes, such as quitting smoking and reducing exposure to toxins in the environment may restore a temporary loss of smell In some cases, though, smell loss may be permanent.

Hyposmia or anosmia resulting from brain trauma, surgery or neurological damage may not be treatable. A decline in the ability to smell resulting form Alzheimer’s disease or even typical aging may be permanent too. If the loss of smell is permanent, counseling and learning coping strategies, such as how to recognize unsafe food, may help.

Prevention & Prophylaxis

Though in some circumstances, such as aging, smell loss can’t be prevented, there are many things anyone can do to protect the sense of smell. Treating and managing temporary cause s of smell loss, such as sinus infections, allergies and other causes of nuns irritation can protect the sense of smell. Quitting smoking is also important for preserving a healthy sense of smell.

A healthy diet rich in essential nutrients such as zinc and thiamin can also keep the sense of smell healthy, and so can exercise. Since head injuries can cause a temporary or permanent loss o smell, health experts advocate taking precautions such as wearing helmets during sports and making other efforts to avoid any kind of injury to the head or face.

Regularly exercising the sense of smell, such as paying attention to smells in daily life and challenging the nose with new ones, can also help. Aromatherapy – the use of scents for healing – may also help stimulate the sense of smell. Since some medications can also contribute to a reduced sense of smell, it may be helpful to review them or ask for a change in prescription.

A keen sense of smell is an important if often overlooked aspect of health. Though a loss or reduction in the ability o smell is not life threatening in itself, it can be a symptom of many conditions. Depending on what’s causing the problem, smell loss can be successfully treated – and in many cases prevented, with lifestyle changes anyone can make.