The loss or absence of taste is defined as ageusia.

Physiologically, ageusia may be summarized as follows: transport interference within the taste bud receptor cells; receptor cell injury and gustatory nerve damage. The factors associated with these categories are as follows:

• Transport Gustatory Losses are associated with hyposalivation (decreased saliva production) and associated dry mouth. The reduced saliva may be caused by heavy metal toxicity or bacterial infection of the taste buds.
• Sensory Gustatory Losses are secondary to degeneration and inflammation of the oral cavity. Some drugs, radiation therapy to the oral cavity, viral infections, endocrine disorders, aging and neoplasms may be implicative factors.
• Neural Gustatory Losses result from injury to gustatory afferents to the central nervous system. This injury is usually degenerative.

A dry mouth, and inability to distinguish sweet, sour, bitter, or salt are signs and symptoms of total ageusia. The patient also may have an olfactory loss.

Patients who complain of loss of taste should be evaluated psychophysically for taste loss as well as olfactory loss. The head and neck physical examination must include a thorough nasopharyngeal, nasal passage, oral cavity, and oropharyngeal evaluations. There is a taste-testing for perception of sucrose, caffeine, citric acid, and sodium chloride. Electric taste testing (electrogustometry) may be used to identify taste deficits in specific tongue quadrants. Biopsy of the taste buds is being performed experimentally to categorize taste disorders.

Topical sprays of artificial saliva may be beneficial as well as the treatment of the underlying cause of the disorder (i.e. bacterial and fungal infections).

Therapy for taste loss is limited and no strategies exist for sensorineural disorders.

Special Considerations

• None.

• Evaluation will be assigned under Diagnostic Codes 6275 or 6276 only if there is an anatomical or pathological basis for the condition. ((38 CFR 4.87(a) [Schedule of ratings-other sense organs])