Patients with loss of smell (anosmia) without any other symptoms may be among the hidden COVID-19 carriers according to Professor Claire Hopkins of the British Society of Rhinology. Anosmia as the main symptom of mild coronavirus infection is recorded in Germany in 2/3 of patients with a positive reaction to COVID-19, about 30% – in South Korea. Information about similar symptoms comes also from China, Iran, USA, France and Northern Italy.
“If the decrease or disappearance of the smelling sense occurs suddenly and is not associated with other obvious diseases of the nose or paranasal sinuses (for example, rhinitis, nasal polyposis, sinusitis – an inflammatory disease of the paranasal airways, etc.), taking into account current epidemiological situation there is a high probability of coronavirus infections”, – says Professor Jan Plzak, Ph.D., Head of the Department of Otorhinolaryngology and Head & Neck Surgery, 1st Medical Faculty of Charles University, as well as Chairman of Czech Society of Otorhinolaryngology and Head & Neck Surgery of the Czech Medical Association JEP.
According to the professor patients should not visit their general practitioner or ENT doctor in case of isolated loss of smell, unless they have other breathing problems or other health problems requiring medical attention. “Unfortunately, patients with a sudden loss of smell do not yet meet the accepted criteria for testing or quarantine. But we are guided by the current recommendations of the European Society of Rhinology, as well as the American Academy of ENT and head and neck surgery”, – adds Professor Plzak. Although sudden smelling loss may be caused by other viruses, it is reasonable to assume that COVID-19 is their cause from precaution, if this cannot be ruled out by testing. Therefore, doctors recommend patients who experience a loss of smell repeatedly with no apparent reason, and those who live in the same household follow current quarantine guidelines.
- In general, the most common causes of complete loss of smell (anosmia) or partial (hyposmia) are viruses that cause upper respiratory tract infections often called “colds.” These includes a group of coronaviruses.
- Viruses can affect olfactory function in several ways. The inflammation of the nasal mucosa that they cause can limit the access of inhaled air to the ceiling area of the nasal cavity, where the special olfactory epithelium is located, and also impair the recognition of odors. In addition, the virus can directly attack and damage the cells of the olfactory field in the ceiling of the nasal cavity or damage the neural pathway through which the olfactory perceptions are directed from the nose to the olfactory center in the brain.
- Since olfactory perceptions also play a significant role in taste perception, it’s often affected in the case of olfactory disorders.
Viruses most often enter the human body through the mucous membranes through the mouth, nose and eyes. And people unknowingly stretch to them almost constantly. Therefore, doctors recommend to pay attention to these touches and try to exclude them without preliminary disinfection of the hands due to the high risk of infection.