What is throat infection? A throat infection, sometimes called pharyngitis, can be either a bacterial or a viral infection leading to inflammation of the tissues of the throat that causes redness, pain and swelling of the walls or structures of the throat. Your throat, or pharynx, is the tube-like structure that carries both food to the esophagus and air to your windpipe (called the larynx). Infective agents of the throat most often enter through the mouth or nose. Many of these infections are viral; others can be caused by bacteria (such as Streptococcus pyogenes, or group A Streptococcus). Streptococcal bacteria are the agents that cause the painful and well-known condition known as strep throat. Symptoms of throat infection most commonly include pain and a sensation of heat in the throat or pharynx. The infection may also affect other structures within the throat, in particular the tonsils (when it is referred to as tonsillitis). Symptoms can range from mild to severe and may or may not be accompanied by fever, cough, congestion, and other flu-like symptoms such as body aches. You may also experience swollen lymph nodes in the neck. Most throat infections, particularly those due to viruses, clear up on their own, while certain bacterial infections are easily treated with antibiotics. Seek immediate medical care (call 911) for serious symptoms, such as choking or severe difficulty breathing, which may be combined with pale or blue lips, rapid heart rate (tachycardia), and anxiety; high fever (higher than 101 degrees Fahrenheit); sudden swelling of the tongue or throat structures; change in level of consciousness or alertness, such as passing out or unresponsiveness; or a change in mental status or sudden behavior change, such as confusion, delirium, lethargy, hallucinations or delusions. You may also have less serious symptoms or conditions that should still be evaluated. Seek prompt medical care if you have white patches at the back of your throat or on your tonsils, if you are being treated for throat infection but mild symptoms recur or are persistent, or if you have other concerns.