Less common culprits for declining senses

If you feel your senses may no longer be where they used to be, you don't have to compromise your quality of life. Access the root cause of the problem with these unlikely culprits.

Several nervous system disorders such as migraine, multiple sclerosis, Parkinson's or Alzheimer's disease are associated with smell and taste disorders, and are an often-overlooked cause of reduced appetite, weight loss and depression.

• People suffering from psychiatric conditions such as schizophrenia or anorexia may experience loss of taste and smell.
• Schizophrenia can also cause olfactory hallucinations — smelling something that isn't there, and this may also occur during epileptic seizures.  

• Across all age groups, the most common cause of complete loss of smell — anosmia — is head injury, most often sustained in road accidents.
• About one in twenty patients who have a head injury develop total anosmia, and another 30 per cent have reduced smelling capacity.
• They often also experience distorted smell — innocuous substances smell offensive — sometimes accompanied by unpleasant tastes.
• The symptoms result from damage to the nerve fibres in the area at the top of the nose where smell receptors are located, or are sometimes due to direct injury to the brain.
• The more severe the head injury, the more likely it is that smell will be affected. Loss can sometimes be permanent or recovery may take longer than a year.

• Some types of surgery can upset your sense of taste and smell, especially operations involving the ear, the nose or the sinuses, as well as radiation therapy for certain cancers of the head and neck.
• A tumour behind the nose or in the membranes surrounding the brain can also damage or even destroy your sense of smell.

• Several medical problems that involve damage to the heart and blood vessels (cardiovascular system) are also linked with smell disorders, including heart attacks, stroke, diabetes and high blood pressure — indeed, some scientists think that smell disorders could be used to predict risk for these conditions.
• In some cases, lifestyle factors are responsible for loss of taste or smell, so the cure is within your control.
• Smoking is a common trigger as it irritates the nasal lining and can exacerbate symptoms of nasal polyps.
• Quitting will preserve these senses though it may take years to restore them fully. In addition, toxins such as insecticides and solvents can occasionally impair your sense of smell.
• Although this is rare, it is worth being careful if handling either. Smell disorders can also occur with both malnutrition and obesity, vitamin A deficiency, hormonal disturbances and poor oral hygiene.