Disorders of taste and smell.

Symptoms of disorders in taste and smell range from loss of the sensations to an increased sensitivity. Causes include infections, metabolic disorders, and central nervous system disturbances. In many instances, the diagnosis for these disorders is obvious, such as an upper respiratory tract infection. In some cases, the diagnosis eludes the clinician and no pathologic condition is found. For the idiopathic taste disorders, zinc therapy is available; however, no therapy exists for idiopathic smell disorders.