Causes of a taste disturbance to consider include:
- upper respiratory tract infection - the taste of food is dependent on the smell
- anosmia
- glossopharyngeal nerve palsy - loss of taste on the posterior third of the tongue
- facial nerve palsy
- chronic adrenal insufficiency - increased sensitivity to the taste of salt, sucrose, urea and other substances
A much more detailed list of causes (1,2,3):
Common causes include:
- nasal and sinus disease (e.g., allergic or vasomotor rhinitis, chronic sinusitis, nasal polyps, adenoid hypertrophy)
- upper respiratory infection
- head trauma (e.g., frontal skull fracture, occipital injury, nasal fracture)
- cigarette smoking
- neurodegenerative disease (e.g., Alzheimer's disease, Parkinson's disease, multiple sclerosis)
- increasing age
Less common causes include
- drug induced - see linked item
- cocaine abuse (intranasal)
- toxic chemical exposure (e.g., benzene, benzol, butyl acetate, carbon disulfide, chlorine, ethyl acetate, formaldehyde, hydrogen selenide, paint solvents, sulfuric acid, thrichloroethylene)
- industrial agent exposure (e.g., ashes, cadmium, chalk, chromium, iron carboxyl, lead, nickel, silicone dioxide)
- nutritional factors (e.g., vitamin deficiency [A, B6, B12], trace metal deficiency [zinc, copper], malnutrition, chronic renal failure, liver disease [including cirrhosis], cancer, acquired immunodeficiency syndrome)
- glossopharyngeal nerve palsy - loss of taste on the posterior third of the tongue
- facial nerve palsy
- radiation treatment of head and neck
- congenital conditions (e.g., congenital anosmia, Kallmann's syndrome)
Uncommon causes include:
- neoplasm or brain tumor (e.g., osteoma, olfactory groove or cribiform plate meningioma, frontal lobe tumor, temporal lobe tumor, pituitary tumor, aneurysm, esthesioneuroblastoma, melanoma, squamous cell carcinoma)
- psychiatric conditions (e.g.schizophrenia, depression, olfactory reference syndrome)
- endocrine disorders (e.g., adrenocortical insufficiency, Cushing's syndrome, diabetes mellitus, hypothyroidism, primary amenorrhea, pseudohypoparathyroidism, Kallmann's syndrome, Turner's syndrome)
- pregnancy
- epilepsy (olfactory aura)
- migraine headache (olfactory aura)
- cerebrovascular accident
- Sjögren's syndrome
- Systemic lupus erythematosus
Reference:
- Bromley SM. Smell and Taste Disorders: A Primary Care Approach.Am Fam Physician. 2000 Jan 15;61(2):427-436.
- Prescriber 1999; 10 (12): 94.
- Pulse 2004; 63 (47): 80.