A metallic taste on the tongue may result from infections, oral injuries, medications, and certain diseases and disorders, according to Healthgrades. The condition may also occur due to advanced age, smoking, dehydration, head radiotherapy and mouth dryness.
Sore throat, strep throat, sinusitis and flu constitute some of the infectious causes of metallic taste on the tongue, notes Healthgrades. Oral injuries that may cause the condition are, among others, tongue biting and nasal injury. Being in direct contact with certain insecticides may cause chemical poisoning, leading to metallic taste on the tongue. Antibiotics, bronchodilators, antithyroid medications, penicillamine and lithium are examples of medications that may result in metallic taste on the tongue. Other medications include captopril, which is a medication used in the treatment of cardiac failure and hypertension, and rifampin, which is a drug that helps in the treatment of tuberculosis and prevention of meningitis due to bacteria.
Diseases and disorders that may lead to metallic taste on the tongue include glossitis, which is a condition in which the tongue becomes swollen; dental gingivitis; nasal polyps; and neurological disorders such as Bell's palsy and brain damage, as Healthgrades notes. Others are Sjogren’s syndrome, hay fever and lack of sufficient nutrients such as zinc and vitamin B-12 in the body.