Dysgeusia

Dysgeusia is an alteration or distortion of the sense of taste. People with dysgeusia may notice a persistent metallic, salty, sour, or rancid taste, and flavors may be perceived as different or less distinct. The condition can affect all tastes (hypogeusia or ageusia) or only certain tastes and may be temporary or persistent.

Causes are diverse and include medications, medical treatments, and health conditions. Common drug-related causes involve antibiotics such as metronidazole or tetracyclines, and antihypertensives like captopril, among others. Head and neck radiation, chemotherapy, and other systemic illnesses can disrupt taste receptor function or saliva production. Nutritional deficiencies, particularly zinc or vitamin B12, can contribute. Infections (including viral diseases such as COVID-19), dental infections, periodontal disease, and oral candidiasis are associated with dysgeusia. Endocrine disorders (diabetes, thyroid disease), kidney or liver dysfunction, smoking, and alcohol use may also play a role. Pregnancy can temporarily alter taste perception.

Pathophysiology is multifactorial. Taste receptor cells, saliva composition, and neural pathways conveying taste data to the brain can be affected by injury, inflammation, medications, or metabolic disturbances, leading to distorted perception of flavors.

Diagnosis relies on clinical history and examination. A detailed review of medications, recent illnesses, diet, and oral health is essential. Objective taste testing and laboratory assessments (zinc and B12 levels, thyroid and liver/kidney function, glucose) may be used. Additional imaging or neurological evaluation is considered when neurological symptoms are present.

Management focuses on the underlying cause when possible. This may involve changing causative medications, treating infections, correcting nutritional deficiencies, improving oral hygiene, and addressing dry mouth. Zinc supplementation should be guided by a clinician, and prognosis varies with etiology.

See also: ageusia, hypogeusia, anosmia.