Ageusia is the inability to taste. True ageusia is quite rare, and it can be caused by a number of things. More commonly, people have what is known as a “taste disorder,” meaning that their sense of taste is impaired, but not entirely absent. Many taste disorders are linked to smell disorders since the experiences of smell and taste are very closely related. People who suffer from ageusia often seek medical attention, since taste is viewed as a critical sense by many humans.
In true ageusia, a patient cannot taste anything applied to his or her tongue. More commonly, people have hypogeusia, a taste disorder in which the patient has trouble differentiating tastes or experiencing certain tastes. Older people, for example, tend to be less sensitive to bitter flavors. People can also develop dysgeusia, in which the sense of taste is distorted or altered.
On its own, ageusia is a problem for many sufferers because it interferes with the enjoyment of food. Someone with ageusia may eat substantially less than he or she should, potentially experiencing malnourishment. The sense of taste is also critically important in detecting signs that food has gone “off,” in combination with the sense of smell, which means that someone with ageusia may eat something which makes him or her sick.
Congenital ageusia, in which someone is born without a sense of taste, is very unusual. More commonly, the condition is acquired as a result of neurological problems, endocrine issues, or localized problems such as infection, inflammation, or damage to the tongue. Smokers and drinkers also tend to experience ageusia because their taste buds are desensitized by their habits.
To diagnose ageusia, a doctor usually performs a taste test, determining which tastes people can detect, and at which concentrations. Taste testing kits are available for this purpose, allowing doctors to use carefully calibrated tastes to test their patients. The doctor may also review the patient's history to get at the underlying cause of the problem, and to determine a course of treatment.
Treatments for ageusia vary, depending on the cause of the condition. A healthy smoker, for example, might be able to resolve the problem by cutting back on smoking or quitting altogether. Someone with a neurological or endocrine problem might discover that the ageusia will be resolved if the underlying medical condition is addressed with medication, surgery, or other forms of medical therapy.