Anosmia is a condition in which a person completely loses the sense of smell. Depending on the reason for its loss, the condition may be temporary or permanent. Common causes of temporary anosmia include colds, allergies and sinus infections, and viral infections such as the flu. Anosmia may also be caused by something physically blocking the flow of air through the nose such as nasal polyps. Aging may also play a role in the progressive loss of smell over time.
Colds or allergies may cause irritation to the mucous membranes lining the inside of the nose, resulting in temporary anosmia. Obstructions of the nasal passages such as polyps, tumors or bone deformities may also cause anosmia. Other causes of total or partial loss of smell include:
Certain diseases including Alzheimer's disease, Parkinson's disease and multiple sclerosis can also affect the sense of smell.
Chronic anosmia may be diagnosed through a physical examination of the interior of the nose through a nasal endoscopy. An MRI or CT scan may also be performed to investigate any underlying causes of anosmia. Olfactory nerve testing may also be performed.
Treatment of anosmia depends on its cause. When caused by a viral infection or an allergic reaction, it will usually clear up on its own, though an over-the-counter decongestant may open the nasal passages and provide some relief. If anosmia results from an infection, an antibiotic may be prescribed. When it is the result of a nasal polyp or other obstruction, surgery may be required. If anosmia is caused by a particular medication, discontinuing taking the medication or substituting another may be done under a doctor's supervision. For some patients, anosmia may provide a reason to give up smoking or using cocaine. However, If the anosmia is caused by aging or a disease, there may be no effective remedy for treatment.
The sense of smell often serves as a warning signal, alerting people to the smoke of a fire, or spoiled food. It is important for people with anosmia to have smoke detectors in the home, and to make sure food has not spoiled or become contaminated before consuming it.