Smell disorders, also known as olfactory disorders, refer to conditions that affect a person's ability to detect or identify odors. These disorders can manifest as a reduced sense of smell, complete loss of smell, or distorted smell perception. Common causes include nasal congestion, head injuries, infections, and certain neurological conditions like Alzheimer's disease. Individuals with smell disorders may experience challenges in daily life, such as difficulty enjoying food or detecting hazards like smoke or gas. Diagnosis typically involves a medical history review and smell tests. Treatment options vary based on the underlying cause and may include medications or therapies to improve olfactory function.