Smells accompany people, even more than taste, throughout their lives. Smells not only convey information, they also influence feelings. A pleasant or unpleasant scent or taste warns people, triggers a sense of well-being or conveys pleasure. The sense of smell and the sense of taste are closely related. Every year, around 50,000 people in Germany suffer disorders of the sense of smell and taste – for example, in the case of sinusitis or Parkinson’s disease. Even a simple cold can significantly impair sensation. However, infection with coronavirus can also lead to a loss of sense of smell and taste, which is why COVID-19 is suspected in this symptom.
Can you taste without smelling?
The smell of freshly ground coffee, of fresh bread, rolls or of cookies at Christmas time awakens feelings and memories in everyone and makes “one’s mouth water“. But the sense of smell is even more closely linked to the sense of taste, as most people should know who have already eaten their favorite foods during a cold with a blocked nose and found that they suddenly tasted completely different. After all, food and drink taste bland with the tongue alone, and eating is no fun if you can’t smell it, too. So the senses of taste and smell have to work together to create a harmonious whole. Blocked nose – what to do? Tips and home remedies
Connection of sense of smell and taste
Sense of smell (by the way, the technical term is olfactory perception) and sense of taste (referred to in technical language as gustatory perception) are chemical senses: in the process, the invisible molecules of the source substances reach the olfactory mucosa through the mouth and nose. Salty, sweet, sour, bitter, umami (savory, meaty, spicy) – the tongue recognizes only these five tastes with the help of its taste buds. From there, special cell assemblies called receptors transmit the perceived taste to the brain via various cranial nerves. The nose, on the other hand, can distinguish thousands of odors. The olfactory cells, also called “olfactory sensory cells,” are activated by odors. Almost all of these nerve cells are located in a small area in the roof of the nasal cavity, in the olfactory epithelium. This is where millions of olfactory cells are located. From there, signals are sent directly to the brain via the olfactory nerve. In the brain, the information passed on by the sensory cells is linked together, which then allows aromas to be recognized and assigned. The trigeminal nerve, the sensory nerve, plays an important role in the interaction between smell and taste: this cranial nerve, which splits into three branches extending to the eye, upper jaw and lower jaw, conveys sensations such as the burning sensation of chili or the cooling effect of menthol.
Disturbances of the senses of taste and smell
The senses of taste and smell can be affected independently or both together by various disorders:
- “Hyposmia” is what medicine calls it when the sense of smell is partially lost.
- “Anosmia” is the technical term for the complete destruction of the sense of smell.
- Parasomia is when odors are misperceived (usually odors are perceived as unpleasant).
- A taste disorder or taste disorder is called dysgeusia.
- A complete loss of the sense of taste is called ageusia.
- If taste sensations are perceived incorrectly, it is called parageusia.
Sense of smell lost: These are possible causes.
If the sense of smell is gone, this can have various reasons. A common cause for a temporary loss of the sense of smell is in most cases a cold with rhinitis. Here it is swelling of the nasal mucosa that leads to impairment of the sense of smell. Flu viruses also colonize the mucous membranes and can temporarily disrupt the epithelium of the olfactory mucosa. Similarly, nasal polyps or sinusitis impair the sense of smell. Sensory perceptions return after the condition subsides. The sense of smell can also be impaired in smokers and people who, for example, work a lot with strong-smelling chemicals at work. In rare cases, a disorder of the sense of smell is also congenital.
Olfactory disorders in Alzheimer’s and Parkinson’s disease
In addition, central olfactory disorders can also be present in the brain, for example in diabetes, high blood pressure, malnutrition or malnutrition. Some medications can also interfere with the sense of smell and taste. Studies have shown that around 80 percent of all Parkinson’s and Alzheimer’s patients experience olfactory disorders at an early stage. In both diseases, the causes of the olfactory disorders do not lie in disturbed olfactory sensory cells, but directly in the brain. From around the age of 65, the ability of the olfactory cells to regenerate decreases. Taste perception also declines, although not as strongly. Many older people therefore sometimes season their food too strongly and prefer sweet foods. From the age of 80, 80 percent of the population suffers from disorders of the sense of smell and taste.
Sense of taste lost: possible reasons
Loss of the sense of taste can also have harmless causes such as a cold. In addition, disorders of taste in the area of the taste buds can also result from iron or vitamin B12 deficiency, as well as kidney or liver disease, or as a side effect of certain medications. In addition, damage to the brain or cranial nerves, for example as a result of tonsillectomy, ear surgery, encephalitis, or diseases such as multiple sclerosis and Parkinson’s disease can also be responsible for a lost sense of taste.
Corona: COVID-19 as a cause of the disorders.
Possible symptoms of infection with SARS-CoV-2 include and impairment or even loss of the senses of smell and taste. While the exact causes are not yet clear, it is becoming apparent that the disturbances are usually temporary. However, there is considerable variation in duration.
- The taste buds, which consist of skin cells, need about two weeks to regenerate after damage, which is why the sense of taste is back quite quickly in many affected people after the disease has subsided.
- The loss of the sense of smell, on the other hand, can last for several months. Because in the case of an infection with the coronavirus, the disturbance of smelling does not arise as in a cold by a swollen nose, but by damage to the sensory cells of the olfactory system. In this case, the sensory cells are not skin cells but nerve cells (neurons). Until these have renewed, several months may pass.
Diagnosis: What the doctor does
To find out the cause of the disease, the doctor examines the nose, nasal mucosa and nasopharynx. He then tests the sense of smell separately on both sides and also does a taste test. A check of the patency of the nose and an allergy test are also required to rule out an allergy. If necessary, the paranasal sinuses are examined with the aid of X-rays or computer tomography. If a corona infection is suspected, the physician will arrange for a test for COVID-19. Only if the complaints cannot be explained in this way will the doctor check whether the cause is in the brain.
What can you do if you no longer have a sense of smell?
In the case of a loss of the sense of smell or the sense of taste, it is always necessary to first clarify the cause. So the first step is always to go to the doctor so that he can perform the appropriate tests. Depending on the diagnosis, he can then select the appropriate treatment. The therapy of the underlying disease is always in the foreground. This can be done, for example, with medications or nutritional supplements, or it may even require surgery. Coronavirus: typical symptoms in COVID-19.
