General Information
The Taste and Smell Clinic at the University of
Connecticut Health Center appreciates your interest. As of
1996, we have gathered information on over 3,000 people with
taste and/or smell problems. Over 1,000 of these individuals
have traveled to our Center for comprehensive evaluation.
Basically, we provide our patients with the following
services: (1) Documentation of the type and severity of the
taste and/or smell problem; (2) Determination of probable
cause(s); (3) Management, if the condition is determined to
be treatable (less than half of patients); and (4)
Computerized maintenance of patient records (allowing future
contact should an appropriate treatment become available).
It is estimated that approximately 2 million adult
Americans have a taste and/or smell disorder. These include
anosmia (complete smell loss), hyposmia (partial smell
loss), ageusia (complete taste loss), hypogeusia (partial
taste loss), parosmia (smell distortion or phantom smell),
and dysgeusia (persistent abnormal taste). There are
actually three "chemosensory" systems in the nose and mouth.
The first, olfaction, is the ability to detect and identify
odors. The second is gustation or taste. Taste function is
limited to detection and identification of sweet, sour,
salty, and bitter substances in the mouth. The third sense,
the "common chemical sense", is the ability to detect the
irritating properties of substances in the mouth and odors
in the nose. Through the common chemical sense, we perceive
the burn of chili pepper and the tingle of ammonia.
Information about taste is picked up by numerous taste
buds distributed throughout the oral cavity. Smell
information is processed by specialized nervous tissue at
the very top of the nasal cavities. The common chemical
sense is transmitted through many tiny nerve endings in the
linings of the nose and mouth. Information from these three
senses is transmitted via a number of separate paths to the
brain.
The terms "flavor" and "taste" are often confused. Flavor
is determined by the aroma (smell), taste (sweet, sour,
salty or bitter quality), texture, temperature and spiciness
(or irritation) of food and beverages. All of these sensory
experiences together form "flavor." Frequently, when
individuals say they cannot taste, they are really telling
us that they cannot appreciate the flavor of food. As the
aroma of food contributes to about 3/4 of its flavor, these
individuals usually have suffered a loss of smell ability
only.
Once the type of chemosensory problem is determined,
preferably through testing, the cause needs to be
identified. Although taste and smell abnormalities are
linked to many medical and dental conditions, most are
caused by only a handful of disorders.
Life-long Anosmia
Some people are born without an ability to smell. This is
called congenital anosmia. There are many possible reasons
for a life-long inability to smell. The most commonly
described, although it occurs in only 1 in 50,000 females
and 1 in 10,000 males, congenital anosmia is Kallman's
syndrome. This syndrome can run in families and is
manifested chiefly by smell loss and hormonal problems that
prevent the development of normal sexual characteristics. In
women, this might be evidenced by lack of onset of normal
menstruation, poor breast development, sparse or absent
axillary and pubic hair. Men might exhibit small testicles
and penis, sparse or absent facial, axillary or pubic hair.
Sterility might be present. If you can never remember being
able to smell, and have noted abnormal sexual development in
yourself or in close family members, you might want to
consult an endocrinologist (hormone specialist) in your area
for evaluation.
Some individuals who can not remember ever being able to
smell were born with a normal smell system, but lost this
ability during childhood. The two most likely causes for
this are head trauma and viral infection. Data obtained from
adults show that even insignificant head trauma can lead to
permanent and total smell loss. Minor blows to the head are
common in childhood. It is likely that some children labeled
as "congenital anosmics" were born with an intact smell
system, but damaged this system during childhood. Viral
respiratory infections (the common cold) have also been
known to damage the smell system (see below). It is possible
that some children sustained permanent injury to the smell
system through a viral infection when very young.
Viral Damage and Nasal/Sinus Disease
Learn more >
Head Trauma
Learn more >
Exposures
The specialized smell tissue at the top of the nose can
also be damaged by environmental agents, such as chemicals,
metal dusts and wood dusts. These can be encountered in the
home or workplace. Both acute and chronic exposures have
been reported to cause both temporary and permanent smell
losses.
Other Causes
Rarely, a specific type of benign brain tumor can cause
smell loss. Any individual who has developed a gradual
decrease in smell function and who is not determined to have
any of the other possible causes listed above should
consider evaluation for this tumor. Though rare, it is
treatable.
Taste and smell problems have also been linked to many
medical illnesses, and have been reported as a side effect
to medications, surgery and radiation therapy. These are too
numerous to list here. For a more comprehensive list, please
refer to the following reviews: Mott AE and Leopold DA,
"Disorders in Taste and Smell", Medical Clinics of North
American, 6:1-33, 1991; Mott AE, Grushka M, and Sessle BJ,
"Diagnosis and Management of Taste Disorders and Burning
Mouth Syndrome", Dental Clinics of North America,
37(1):1993.
Special Instructions for Patients with Smell Loss
The ability to smell allows early detection of dangerous
substances in our environment and the loss of this sensory
system places an individual at risk. These risks can be
minimized, however, by instituting certain precautionary
measures. If you have not already done so, please make
certain smoke detectors are present and functional in your
home. They should be checked every month. Also, if you are
exposed to potential gas leaks, we would encourage you to
purchase a gas detector. Information about this may be
obtained through your local gas company or a marine store
(the inability to detect smoke and/or leaking gas are two
potential hazards for those without smell function).
Patients should also be exceptionally careful with food and
beverages. Refrigerated food should be date-labeled and
stored at appropriate temperatures. All food should be
inspected prior to preparation and eating. Food that looks
spoiled should be discarded. Preferably, a member of the
household with an intact smell system should check any food
or beverage that is questionable.
We hope this information is useful to you. Please let us
know if we can provide additional information to you or your
physician/dentist.
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