How do people lose their sense of smell?
There are many possible causes for smell disturbances and changes. Damage to the olfactory system can be temporary but it is more commonly lasting and irreversible. Some common causes of permanent damage are upper respiratory infections and rhino sinusitis (more commonly known as a sinus infection). Head trauma that results in damage to nerves in or around the nose is another primary cause of smell loss (Doty, 2003). Exposure to a number of toxic agents can induce smell loss or damage, and some prescription drugs occasionally interrupt normal smell perception (Schiffman, 1983)

There are a number of serious medical conditions, e.g. neurodegenerative diseases that are often associated with olfactory problems. Epilepsy, multiple sclerosis, Parkinson’s disease, and Alzheimer’s disease are all proven to be linked to olfactory impairment in some form or another. In fact, doctors have determined conclusively that smell is one of the first senses to fail as Alzheimers Disease progresses. Therefore, tracking the onset of smell loss can play a vital role in early Alzheimer’s detection (Doty, 2003).

There are several psychiatric disorders linked to an altered sense of smell, such as schizophrenia, hallucinatory psychoses, seasonal affective disorder, and severe anorexia nervosa and Multiple Chemical Intolerance (Miller, 2003).

Smell loss, to varying degrees, is a natural part of the aging process. Fortunately it is a very slow moving process and although people as young as 30 or 40 may have lost some of their ability to smell, it is usually not noticed until much later in life (70’s or 80’s). Elderly people frequently complain of a loss of taste and appetite when it is in fact their sense of smell that has diminished. Dr. Marcia Pelchat’s research at the Monell Chemical Senses Center research concludes elderly individuals are less able to detect weak odors and demonstrate deficits in odor and flavor identification because of elevated thresholds (Compendium of Olfactory Research, 2001).

Abnormalities in the sense of smell often affect the ability to taste because the olfactory system plays such an important role in eating and 80% of food appreciation comes from olfaction. Without the sense of smell, we can only taste sweet, sour, salty, bitter, and savory. All other tastes are determined by the sense of smell. The loss of the great gift of tasting can have a profound consequence on the quality of life. Glaser writes, “without smell, one of life’s greatest pleasures – food – would be scarcely more than fuel, boring and unremarkable”.