para />
Elders are at particular risk of eating spoiled food or inadvertently being exposed to natural gas leaks owing to anosmia from aging.
Anosmia also may be an early sign of degenerative disorders and has been shown to predict increased 5-year mortality (1)[B].
‚
Pediatric Considerations
Smell and taste disorders are uncommon in children in developed countries.
In developing countries with poor nutrition (particularly zinc depletion), smell and taste disorders may occur.
Delayed puberty in association with anosmia ( ‚ ± midline craniofacial abnormalities, deafness, or renal abnormalities) suggests the possibility of Kallmann syndrome (hypogonadotropic hypogonadism).
‚
Pregnancy Considerations
Pregnancy is an uncommon cause of smell and taste loss or disturbances.
Many women report increased sensitivity to odors during pregnancy as well as an increased dislike for bitterness and a preference for salty substances.
‚
COMMONLY ASSOCIATED CONDITIONS
URI, allergic rhinitis, dental abscesses ‚
DIAGNOSIS
Smell and taste disturbances are symptoms; it is essential to look for possible underlying causes. ‚
HISTORY
- Symptoms of URI, environmental allergies
- Oral pain, other dental problems
- Cognitive/memory difficulties
- Current medications
- Nutritional status, ovolactovegetarian
- Weight loss or gain
- Frequent infections (impaired immunity)
- Worsening of underlying medical illness
- Increased use of salt and/or sugar to increase taste of food
- Neurodegenerative disease
PHYSICAL EXAM
Thorough HEENT exam ‚
DIFFERENTIAL DIAGNOSIS
- Epilepsy (gustatory aura)
- Epilepsy (olfactory aura)
- Memory impairment
- Psychiatric conditions
DIAGNOSTIC TESTS & INTERPRETATION
Initial Tests (lab, imaging)
Consider (not all patients require all tests) ‚
- CBC
- Liver function tests
- Blood glucose
- Creatinine
- Vitamin B12 level
- Thyroid-stimulating hormone (TSH)
- Serum IgE
- CT scanning is the most useful and cost-effective technique for assessing sinonasal disorders and is superior to an MRI in evaluating bony structures and airway patency. Coronal CT scans are particularly valuable in assessing paranasal anatomy (2)[B].
Follow-Up Tests & Special Considerations
Diagnosis of smell and taste disturbances is usually possible through history; however, the following tests can be used to confirm: ‚
- Olfactory tests
- Smell identification test: evaluates the ability to identify 40 microencapsulated scratch-and-sniff odorants (3)[B]
- Brief smell identification test (4)[B]
- Taste tests (more difficult because no convenient standardized tests are presently available): Solutions containing sucrose (sweet), sodium chloride (salty), quinine (bitter), and citric acid (sour) are helpful.
- An MRI is useful in defining soft tissue disease; therefore, a coronal MRI is the technique of choice to image the olfactory bulbs, tracts, and cortical parenchyma. Possible placement of an accessory coil (TMJ) over the nose to assist in imaging.
TREATMENT
GENERAL MEASURES
- Appropriate treatment for underlying cause
- Quit smoking (5)[B].
- Treatment of underlying nasal congestion with nasal decongestants and/or nasal/oral steroids (6,7,8 and 9)[B]
- Surgical correction of nasal blockage/nasal polyps (10)[B]
- Some drug-related smell or taste loss or dysgeusias can be reversed with cessation of the offending medication, but it may take many months (11,12,13 and 14)[B].
- Stop repeated oral trauma (e.g., appliances, tongue-biting behaviors).
- Proper nutritional and dietary assessment (2)[C]
- Formal dental evaluation
MEDICATION
- Treat underlying causes as appropriate. Idiopathic cases will often resolve spontaneously.
- Consider trial of corticosteroids topically (e.g., fluticasone nasal spray daily to BID) and/or systemically (e.g., oral prednisone 60 mg daily for 5 to 7 days) (6)[B].
- Zinc and vitamins (A, B complex) when deficiency is suspected (15)[B]
ISSUES FOR REFERRAL
- Consider referral to an otolaryngologist or neurologist for persistent cases.
- Referral to a subspecialist at a regional smell and taste center when complex etiologies are suspected
SURGERY/OTHER PROCEDURES
If needed for treatment of underlying cause ‚
ONGOING CARE
DIET
- Weight gain/loss is possible because the patient may reject food or may switch to calorie-rich foods that are still palatable.
- Ensure a nutritionally balanced diet with appropriate levels of nutrients, vitamins, and essential minerals.
PATIENT EDUCATION
- Caution patients not to overindulge as compensation for the bland taste of food. For example, patients with diabetes may need help in avoiding excessive sugar intake as an inappropriate way of improving food taste.
- Patients with chemosensory impairments should use measuring devices when cooking and should not cook by taste.
- Optimizing food texture, aroma, temperature, and color may improve the overall food experience when taste is limited.
- Patients with permanent smell dysfunction must develop adaptive strategies for dealing with hygiene, appetite, safety, and health.
- Natural gas and smoke detectors are essential; check for proper function frequently.
- Check food expiration dates frequently; discard old food.
PROGNOSIS
- In general, the olfactory system regenerates poorly after a head injury. Most patients who recover smell function following head trauma do so within 12 weeks of injury.
- Patients who quit smoking typically recover improved olfactory function and flavor sensation.
- Many taste disorders (dysgeusias) resolve spontaneously within a few years of onset.
- Phantosmias that are flow-dependent may respond to surgical ablation of olfactory mucosa.
- Conditions such as radiation-induced xerostomia and Bell palsy generally improve over time.
COMPLICATIONS
- Permanent loss of ability to smell/taste
- Psychiatric issues with dysgeusias and phantosmia
REFERENCES
11 Pinto ‚ JM, Wroblewski ‚ KE, Kern ‚ DW, et al. Olfactory dysfunction predicts 5-year mortality in older adults. PLoS One 2014;9(10):e107541.22 Malaty ‚ J, Malaty ‚ IA. Smell and taste disorders in primary care. Am Fam Physician 2013;88(12):852 " “859.33 Doty ‚ RL, Shaman ‚ P, Dann ‚ M. Development of the University of Pennsylvania smell identification test: a standardized microencapsulated test of olfactory function. Physiol Behav 1984;32(3):489 " “502.44 Jackman ‚ AH, Doty ‚ RL. Utility of a three-item smell identification test in detecting olfactory dysfunction. Laryngoscope 2005;115(12):2209 " “2212.55 Frye ‚ RE, Schwartz ‚ BS, Doty ‚ RL. Dose-related effects of cigarette smoking on olfactory function. JAMA 1990;263(9):1233 " “1236.66 Seiden ‚ AM, Duncan ‚ HJ. The diagnosis of a conductive olfactory loss. Laryngoscope 2001;111(1):9 " “14.77 Deems ‚ DA, Doty ‚ RL, Settle ‚ RG, et al. Smell and taste disorders, a study of 750 patients from the University of Pennsylvania Smell and Taste Center. Arch Otolaryngol Head Neck Surg 1991;117(5):519 " “528.88 Apter ‚ AJ, Gent ‚ JF, Frank ‚ ME. Fluctuating olfactory sensitivity and distorted odor perception in allergic rhinitis. Arch Otolaryngol Head Neck Surg 1999;125(9):1005 " “1010.99 Mott ‚ AE, Cain ‚ WS, Lafreniere ‚ LG, et al. Topical corticosteroid treatment of anosmia associated with nasal and sinus disease. Arch Otolaryngol Head Neck Surg 1977;123(4):367 " “372.1010 Olsson ‚ P, Stj ƒ ¤rne ‚ P. Endoscopic sinus surgery improves olfacton in nasal polyposis, a multi-center study. Rhinology 2010;48(2):150 " “155.1111 Naik ‚ BS, Shetty ‚ N, Maben ‚ EV. Drug-induced taste disorders. Eur J Intern Med 2010;21(3):240 " “243.1212 Ackerman ‚ BH, Kasbekar ‚ N. Disturbances of taste and smell induced by drugs. Pharmacotherapy 1997;17(3):482 " “496.1313 Cowart ‚ BJ. Taste dysfunction: a practical guide for oral medicine. Oral Dis 2011;17(1):2 " “6.1414 Tuccori ‚ M, Lapi ‚ F, Testi ‚ A, et al. Drug-induced taste and smell alterations: a case/non-case evaluation of an Italian database of spontaneous adverse drug reaction reporting. Drug Saf 2011;34(10):849 " “859.1515 Henkin ‚ RI, Martin ‚ BM, Agarwal ‚ RP. Efficacy of exogenous oral zinc in treatment of patients with carbonic anhydrase VI deficiency. Am J Med Sci 1999;318(6):392 " “405.
CODES
ICD10
- R43.9 Unspecified disturbances of smell and taste
- R43.1 Parosmia
- R43.2 Parageusia
- R43.0 Anosmia
- R43.8 Other disturbances of smell and taste
ICD9
781.1 Disturbances of sensation of smell and taste ‚
SNOMED
- 275462005 disorders of smell (disorder)
- 399993004 Disorder of taste (disorder)
- 44169009 Loss of sense of smell (finding)
- 271801002 Taste sense altered (finding)
- 112105008 Sense of smell altered (finding)
CLINICAL PEARLS
- Smell disorders are often mistaken as decreased taste by patients.
- Most smell loss is due nasal passage obstruction.
- Actual taste disorders are often related to dental problems or medication side effects.
- Gradual smell loss is very common in the elderly; extensive workup in this population may not be indicated if no associated signs/symptoms are present but may be predictive of 5-year mortality.