What causes loss of smell?
1. The most common cause of loss of smell (also called anosmia) is secondary to a viral infection such as cold or flu. This is usually temporary. Occasionally, it can result in long-term decrease in smell.
2. Chronic illnesses such as diabetes can result in loss of smell. Approximately 50% of diabetic patients experience a decrease in smell. 90% of patients with Alzheimer’s have significant decrease in their sense of smell.
3. There is also a decrease in smell acuity with aging and 25% of people over the age of 55 have a decrease in smell. This increases to 50% of people past the age of 80.
4. Many neurological disorders are also associated with decrease in smell. Injury to the smell or olfactory nerve is the most common nerve injury secondary to head trauma. A decrease in smell almost always affects the ability to taste. So most people complain of loss of both smell and taste.
5. Loss of smell may also be experienced by patients who have chronic sinusitis. This is significantly increased if nasal polyps are present. Treatment of chronic sinusitis and removal of nasal polyps frequently results in improvement in smell. However, long-term studies have show that not all patients with chronic sinusitis experience significant improvement in smell following surgical treatment. Results quoted are about 60% of patients demonstrate improvement.
what treatment options are available?
Medical treatment is relatively limited. In appropriate cases, use of a topical or systemic steroid may be indicated. Medications such as fluticasone nasal spray or prednisone may be prescribed. If nasal polyps are present, surgical management is appropriate. Managing underlying allergies is also helpful. Patients with long-term loss of smell may benefit from smell retraining. This involves sniffing essential oils to retrain neural networks recognizing odors.