Smelling Disorders Health Article

Types of smelling disorders

Smelling disorders differ in the way that the sense of smell is affected and how long a person has the disorder. For example, anosmia, the loss of the sense of smell, is often a temporary symptom of a cold or flu. However, a head injury could cause permanent anosmia. In addition, a head injury could produce dysosmia, the distorted sense of smell that could cause a person to hallucinate a foul odor.

Smelling disorders are categorized as:

• Anosmia, the loss of the sense of smell. It is the most common smelling disorder. This condition can be temporary or permanent.
• Dysosmia is a distorted sense of smell. A person senses non-existent unpleasant odors. It can be caused by medical and mental conditions.
• Hyperosmia is an increased sensitivity to smell. It can be a characteristic of someone with a neurotic or histrionic personality.
• Hyposmia is the diminished sense of smell. This is usually a temporary condition that a person may experience after a case of acute influenza. Sometimes this condition is referred to as partial anosmia.
• Presbyosmia refers to the lessening or loss of the olfactory sense that occurs when a person ages.

Smelling disorder demographics

Anosmia occurs in about 10% of head trauma injuries, and head trauma is a leading cause of anosmia in young adults. In older adults, the disorder is generally caused by viral infection. Aging may also bring a loss of the sense of smell. In rare cases, anosmia is inherited. It is a symptom of male hypogonadism (Kallmann's syndrome).

Olfactory hallucinations known as dysosmia are generally associated with psychological conditions. In some cases, people may believe they are the source of foul odors.

Causes and symptoms

Anosmia is the most common type of smelling disorder. Loss of the olfactory sense is generally caused by nasal congestion or obstruction. Temporary partial anosmia often occurs when a person has a cold, the flu, or some types of rhinitis, especially hay fever (allergic rhinitis). During these conditions, nasal mucus membranes become inflamed. Other causes for anosmia are:

• Nasal polyps and other disorders that prevent air from getting to the area in the nose where the smell receptors are found. Hay fever or an allergy may cause one or more polyps to show up.
• Viral upper respiratory infection.
• Atrophic rhinitis. This condition causes mucus membrane to waste away. The person may experience some level of permanent anosmia. One symptom of this condition is that a person expels a foul-smelling discharge.
• Hypertrophic rhinitis. Mucous membrane thickens, covering the olfactory nerve endings. If not treated, hypertrophic rhinitis can lead to permanent anosmia. This discharge could overpower other odors.
• Cigarettes. Smoking aggravates the nose's membrane and intensifies nasal polyp symptoms.
• A crooked nose or a deviated septum.
• When the olfactory bulbs, tracts, or central connections are destroyed. This can occur in situations such as head trauma, infections or nasal or sinus surgery.
• Head injury. If both olfactory nerves are torn during a head injury, permanent anosmia results.
• Medications such as antihistamines and decongestants, especially prolonged use of decongestants.
• Drugs like amphetamines, estrogen, naphazoline, phenothiazines, and resperine.
• The aging process may cause the sense to lessen. In most cases, there is no other obvious cause for the disorder.
• A tumor behind the nose or in the membranes surrounding the brain.
• Lead poisoning.
• Exposure to insecticides or other chemicals.
• Radiation therapy.
• Nervous disorders.
• Idiopathic loss, which means there is no diagnosable cause for the condition.