Anosmia, or loss of the sense of smell, proves a relatively common disorder, especially among older adults. The National Institute of Dental and Craniofacial Research states that approximately 1 to 2 percent of the North American population reports an impaired sense of smell. Anosmia can occur with a variety of disorders, ranging in severity from allergies to head trauma. Treatment for anosmia depends on the underlying cause of the condition.
Nasal Steroid and Antihistamine Sprays
Nasal allergies, or allergic rhinitis, often interfere with the sense of smell, notes the National Library of Medicine encyclopedia MedlinePlus. The primary smell receptors reside in the upper area of the nose. The chemicals in the air that produce scents must reach this area for the perception of smell to occur. Swelling of the nasal tissues associated with allergies can significantly block airflow in the nose, preventing the aromatic chemicals in the air from reaching the smell receptors.
Nasal steroid and antihistamine sprays can help reduce the allergy-induced inflammation of the tissues lining the nose. With reopening of the nasal passages and restoration of airflow, the sense of smell usually returns. Depending on the severity of a patient's allergies, doctors may recommend over-the-counter or prescription medication.
Nasal Polypectomy
Nasal polyps--noncancerous growths inside the nose--commonly block nasal airflow, interfering with the sense of smell. Patients with nasal polyps that fail to shrink in response to medications commonly require surgery to reestablish airflow through the nose and sinuses, notes Dr. Howard Levine on the website of the American Rhinologic Society. An ear, nose and throat specialist removes the nasal polyps using a small fiber-optic instrument inserted into the nose. Most patients regain their sense of smell after surgery, although a small percentage do not.
Oral Steroids
Oral steroids may help some patients with anosmia regain their sense of smell. In a February 2001 article published in the medical journal "The Laryngoscope," Dr. Michael Stevens reports that a significant number of study patients who remained without a sense of smell after a nasal polypectomy regained some function with oral steroid treatment. The mechanism by which steroids benefit patients in this setting remains an area of active biomedical research.
Dr. Rong-San Jiang and colleagues report in an April 2010 article published in the "European Archives of Otorhinolaryngology" that approximately 16 percent of patients with anosmia caused by head trauma had a partial return of their sense of smell with high-dose steroid treatment. Post-traumatic anosmia commonly proves permanent. Therefore, the response in some of the study participants led the authors to conclude that additional research is required to determine which patients may benefit from steroid therapy after a traumatic loss of the sense of smell.
References
- National Institute of Dental and Craniofacial Research: Smell Disorders
- MedlinePlus: Allergic Rhinitis
- American Rhinologic Society: Nasal Polyps
- "The Laryngoscope"; Steroid-Dependent Anosmia; Michael H. Stevens M.D.; February 2001
- "European Archives of Otorhinolaryngology"; Steroid Treatment of Posttraumatic Anosmia; Rong-San Jiang, M.D., et al.; April 2010
