dysgeusia (taste disorder)

Introduction

Impairment of taste.

Etiology

• impairment of access to receptors in the taste buds
  • xerostomia
    • Sjogren's syndrome
    • heavy metal intoxication
    • bacterial colonization of the taste pore
    • hyponatremia
• injury to taste receptor cells (sensory loss)
  • inflammatory or degenerative disease in the oral cavity
    • thermal or chemical burn
  • pharmaceutical agents
    • anti-thyroid agents (methimazole, propylthiouracil)
    • antineoplastic agents (cyclophosphamide, methotrexate ..)
    • ACE inhibitors, ARBs, Ca+2 channel blockers (nifedipine)
    • antibiotics (metronidazole, clarithromycin ..)
    • drugs causing xerostomia (anticholinergic agents)
  • radiation therapy to the oral cavity & pharynx
  • viral infections
  • endocrine disorders
    • diabetes mellitus
    • Cushing's syndrome
    • adrenal insufficiency
    • hypothyroidism
  • neoplasms
  • aging
• damage to gustatory afferent nerves
  • neoplasms
  • head trauma
  • surgery
  • exposure to toxins
• CNS causes (general)
  • Alzheimer's disease & other neurodegenerative diseases
  • CNS neoplasms
  • psychiatric disease
  • stroke
• other oral causes
  • dental infection
  • periodontal disease
  • poor oral hygiene
  • burning mouth syndrome
  • candidiasis
  • laceration
  • salivary gland insufficiency (xerostomia)
• nutritional deficiency
• zinc deficiency
• vitamin B12 deficiency
• other pharmaceuticals altering taste
  • acyclovir, allopurinol, amiloride, amitriptyline, amphotericin B, ampicillin, baclofen, buspirone, captopril, chlorpheniramine, desipramine, dexamethasone, diclofenac, dicyclomine, diltiazem, doxepin, enalapril, ethacrynic acid, ethambutol, fenoprofen, gemfibrozil, hydrochlorothiazide, imipramine, labetalol, levamisole, lomefloxacin, mexiletine, nabumetone, nelfinavir, nifedipine, ofloxacin, pentamidine, pentoxifylline, phenytoin, procainamide, prochlorperazine, promethazine, propafenone, propranolol, ritonavir, saquinavir, sulfamethoxazole, sulindac, terfenadine, tetracyclines, trifluoperazine, zidovudine

Pathology

• taste buds remain degenerate when their gustatory afferents are severed, but remain when their somatosensory afferents are severed

Clinical manifestations

• may be complete impairment of taste (sweet, salt, sour, bitter)
• may be partial loss of taste; ability to recognize some, but not other gustatory sensations
• may be specific loss in ability to taste certain foods
• may be a distortion in the perception of taste
• may be gustatory hallucinations

Laboratory

• testing with sucrose, citric acid, caffeine & NaCl
• electrogustometry
• biopsy of foliate or fungiform papillae

Differential diagnosis

• olfactory disorder

Management

• treat xerostomia
• treat infection
• withdraw offending pharmaceutical agents
• zinc & vitamins recommended by some, but evidence of benefit is lacking

More general terms

• sign/symptom

More specific terms

• cacogeusia
• metallic taste

Additional terms

• taste
• taste bud; caliculus gustatorius; Schwalbe corpuscle; gustatory bud