Loss of sense of smell is medically known as anosmia. In this condition, the person fails to distinguish a particular smell. The condition can also differ in a way that a person is not able to perceive some specific smells. The most probable causes for loss of smell are nasal blockages and destruction of the inner mucus lining of nose.
The first stage of any treatment plan is identification of the cause and symptoms. The next step that follows is diagnosis with tests. If the anosmia is temporary, then it is most probably caused by sinus infections, influenza, or common cold. But if the condition persists for a longer duration of time, then it may be due to nasal polyps (benign nasal tumors) or bone deformity in nose, which is blocking the passage of air through nose.
Serious medical concerns are posed only when the causes attribute to traumatic brain injuries, brain tumors, diabetes, pernicious anemia, Klinefelter syndrome, Alzheimer's disease, Kallmann's syndrome, Korsakoff's psychosis, multiple sclerosis, and advanced aging. If a person is born without the ability to smell, the condition is termed as congenital anosmia, which is caused by genetic factors that run in the family. Meningitis in infancy is also a strong reason for anosmia in children. If the condition is not diagnosed on time, then it may lead to loss of smell and taste in the person.
The condition is diagnosed when the person becomes insensitive to odor. The condition is further confirmed if the person is not able to enjoy his food due to loss of sense of smell, thereby experiencing loss of appetite. Below listed are the widely used olfactory tests that are performed to check for olfactory malfunction prior to treatment.
University of Pennsylvania Smell Identification Test (UPSIT): This test was first developed by Dr. Richard Doty. UPSIT is also widely known as the "Scratch and Sniff" Test. The test kit has about 40 standardized micro encapsulated stimuli/odorants for smell, which the patient can self test at home. This test has been successfully tried on over 2,00,000 patients affected by this condition.
Connecticut Chemosensory Test: In Connecticut Chemosensory test there are 11 plastic squeeze bottles, of which 7 contain diluted butanol in deionized water in different concentrations, and the other 4 bottles contain distilled water. Now when the smell test is carried out for the first time, the patient is given two bottles, one with butanol (most diluted version) and the other without butanol. Once the patient figures out the stronger smell, he proceeds to the next stage of testing, where highly concentrated butanol and diluted butanol are used.
The threshold of the patient is identified when he is able to smell the odor correctly in the first four times of the test. A score below 7 confirms anosmia. In the second stage of this test, 8 plastic jars are kept before the patient. All these jars contain a common odorant (ammonia or vicks) that serves as a stimulant for the trigeminal nerve of the patient. Along with this, about 20 food items are also kept to distract the patient. The patient is now asked to identify the odor. If the patient fails this test, then he/she id diagnosed with anosmia.
Treatments include removal of nasal polyps by surgical means, or treatment with drugs and antibiotics. Surgical treatments are recommended only if antibiotics and nasal spray corticosteroids do not reduce inflammation of nasal polyps. Surgical removal of nasal polyps can be performed in two ways: polypectomy (removing the polyp by mechanical suction) and endoscopic sinus surgery (removing the polyp by injection of a tube inside the nose). Antihistamines are used if there is inflammation in mucous membranes of the nose due to which anosmia has been caused.
The most recommended drugs and antibiotics to provide relief from this condition are:
- Metronidazole (antibiotic)
- Ciprofloxacin (antibiotic)
- Cefuroxime (antibiotic)
- Zythromax (antibiotic)
- Amitriptyline (drug)
Anosmia is not a serious condition if it lasts for a short period of time. People with less sense of smell are advised to include zinc supplements in their diet. Also, chain smokers must remember that smoking, over a prolonged period of time may impair their sense of smell.