I read somewhere that many conditions could cause loss of smell or taste. The most common causes of temporary loss are colds, flu and sinus problems. You can also be born with a smell disorder, usually because of a faulty gene.
Sometimes a cause for the loss of smell cannot be found. This happens in about 1 in 5 people who are investigated in a specialist clinic, but in the wider community represents fewer than 5 in a 100 of all cases of smell loss overall. The sense of smell can be lost due to a variety of causes. The most common causes include:
- An injury to the head.
- A stroke.
- Viral infections - colds or flu.
- Diseases affecting the sinuses, such as various forms of sinusitis (including where nasal polyps form), and structural abnormalities.
- Allergies that affect your nose, such as hay fever.
- Taking certain medications - commonly prescribed antibiotics such as amoxicillin, erythromycin, ciprofloxacin and trimethoprim; medicines used in neurological problems such as Parkinson's disease, migraine; muscle relaxants; cardiovascular medicines used for blood pressure and cholesterol (statins); thyroid medicines; antidepressant or mood-stabilising medicines; others such as antihistamines, anti-inflammatories and antifungal medicines.
- Hormone problems such as Cushing's syndrome.
- Dental or mouth problems.
- Exposure to certain chemicals such as benzene, chlorine, formaldehyde, paint solvents and trichloroethylene.
- Exposure to radiation therapy for head or neck cancer.
- Cocaine snorted through the nose.
- Cigarette smoking.
Some other medical conditions may be associated with a complete lack of sense of smell (anosmia), such as epilepsy, Alzheimer's disease, Parkinson's disease and schizophrenia.
The sense of smell, as with all other senses, naturally decreases with age. Rarely, some cancers can also cause anosmia.
