The loss of smell can occur due to nasal congestion or a blockage of the nose. It isn't serious, but it can sometimes be a sign of a nervous system (neurological) condition.
Temporary loss of the sense of smell is common with colds and nasal allergies, such as hay fever (allergic rhinitis). It may occur after a viral illness.
Some loss of smell occurs with aging. In most cases, there is no obvious cause, and there is no treatment.
The sense of smell is often lost with disorders that prevent air from reaching the part of the nose where smell receptors are located (the cribriform plate, located high in the nose). These disorders may include nasal polyps, nasal septal deformities, and nasal tumors.
Other disorders that may cause a loss of the sense of smell include:
- Disorders of the endocrine system
- Head trauma
- Nervous disorders
- Nutritional disorders
- Tumors of the head or brain
Many medications may change or decrease the ability to detect odors.
The sense of smell also enhances your ability to taste. Many people who lose their sense of smell also complain that they lose their sense of taste. Most can still tell between salty, sweet, sour, and bitter tastes, which are sensed on the tongue. They may not be able to tell between other flavors. Some spices (such as pepper) may affect the nerves of the face. You may feel rather than smell them.