February 2019

Taste and Smell Loss Can be a Chronic Disease

After intranasal theophylline 66% of patients reported improved smell function.

Many patients experience a sudden loss of smell which returns within a period of days or weeks. This can be associated with several events such as a common cold, after an allergy attack, following a general anesthesia associated with a surgical procedure. This type of smell loss occurs in many people but it usually reverts back to normal after a few days or within 1-2 weeks. However, smell loss may persist after this initial loss period. When this occurs smell loss is no longer a transient symptom associated with a cold or allergy attack but a chronic disease problem which does not revert back to normal.

For example, there may be as many as 100 million episodes of “colds” or flu like illness in the U.S. in the past year. As many as 10% of these patients may transiently lose some aspect of smell function from which they recover as the cold symptoms recede. Their smell loss may be initially associated with nasal congestion or rhinorhea or some aspect of the flu-like symptoms. When these symptoms recede and disappear, smell loss recedes and the patient regains smell function. Many of us have experienced this type of loss.

However, after the cold recedes and the smell loss persists, this is no longer a transient problem - it becomes a chronic problem. This may occur in as many of 1% of patients who experience a cold or flu–like illness which can account for as many as one million patients who yearly experience chronic smell loss

This type of loss is no longer transient; it is a permanent loss which will not disappear on its own. It will persist. It may become more severe over time such that food flavor is lost. Distortion of taste and/or smell may occur.

In the sense, smell loss can become a chronic disease problem, which if not treated, may persist.

In this sense, smell loss is a chronic disease much like diabetes. It can be treated but usually requires chronic medical treatment to ameliorate the loss. This is true for patients who exhibit chronic smell loss from any cause - following a flu-like illness, severe allergic rhinitis, head injury or systemic anesthesia.

This concept is important to understand since without treatment smell loss will persist. With treatment smell loss may improve and return to or toward normal but chronic use of medication is necessary to maintain normal smell function. If medication is stopped smell loss usually recurs similar to the return of symptoms of diabetes if similar treatment were stopped.