Olfactory disorders: Diagnosis, evaluation, and treatment

The sense of smell, one of the five basic senses that humans have, helps us detect different types of odors. It also plays an important role in the detection of pollutants, toxic gases, or rotten and hazardous foods. Although olfaction is considered less important than the other senses, smell disorders could cause a variety of problems, including reduced taste detection due to the relationship between taste and smell, depression, and overall loss of quality of life. Olfactory dysfunction is one of the first clinical signs of neurological diseases such as Alzheimer's and Parkinson's disease. The olfactory disorder has many etiologies, some of which are more obvious. Most people with olfactory disorders have experienced a recent illness or trauma. Common causes of olfactory disorders include aging, rhinosinusitis, upper respiratory infections, and cerebral lesion; the rest of the cases are less relevant. Since there are limited evidence-based treatments for olfactory disorders, it is necessary to share information about the risks associated with these disorders. This information includes practical and useful screening measures for olfactory dysfunction, appropriate clinical evaluation, patient counseling to prevent injury, health and quality of life management, and the introduction of treatments with higher recovery rates. This review study focuses on the etiology, prevalence, and short-term and long-term consequences of olfactory disorders. Also, diagnostic strategies and new treatment options have been developed and discussed.