Most sore throats are caused by viruses that cause the common cold and flu (influenza). Less often, sore throats are due to bacterial infections.

Viral infections

Viral illnesses that cause a sore throat include:

  • Common cold
  • Flu (influenza)
  • Mononucleosis (mono)
  • Measles
  • Chickenpox
  • Croup — a common childhood illness characterized by a harsh, barking cough

Bacterial infections

Bacterial infections that can cause a sore throat include:

  • Strep throat, which is caused by a bacterium known as Streptococcus pyogenes, or group A streptococcus
  • Whooping cough, a highly contagious respiratory tract infection
  • Diphtheria, a serious respiratory illness that's rare in industrialized nations, but is more common in developing countries

Other causes

Other causes of sore throat include:

  • Allergies. Allergies to pet dander, molds, dust and pollen can cause a sore throat. The problem may be complicated by postnasal drip, which can irritate and inflame the throat.
  • Dryness. Dry indoor air, especially in winter when buildings are heated, can make your throat feel rough and scratchy, particularly in the morning when you first wake up. Breathing through your mouth — often because of chronic nasal congestion — also can cause a dry, sore throat.
  • Irritants. Outdoor air pollution can cause ongoing throat irritation. Indoor pollution — tobacco smoke or chemicals — also can cause chronic sore throat. Chewing tobacco, drinking alcohol and eating spicy foods also can irritate your throat.
  • Muscle strain. You can strain muscles in your throat just as you can strain them in your arms or legs. Yelling at a sporting event, trying to talk to someone in a noisy environment or talking for long periods without rest can result in a sore throat and hoarseness.
  • Gastroesophageal reflux disease (GERD). GERD is a digestive system disorder in which stomach acids or other contents of the stomach back up in the food pipe (esophagus). Other signs or symptoms may include heartburn, hoarseness, regurgitation of stomach contents and the sensation of a lump in your throat.
  • HIV infection. A sore throat and other flu-like symptoms sometimes appear early after someone is infected with HIV. Also, a person who is HIV-positive may have a chronic or recurring sore throat due to a secondary infection. Common problems include a fungal infection called oral thrush and cytomegalovirus infection, a common viral infection that can be serious in people with compromised immune systems.
  • Tumors. Cancerous tumors of the throat, tongue or voice box (larynx) can cause a sore throat. Other signs or symptoms may include hoarseness, difficulty swallowing, noisy breathing, a lump in the neck, and blood in saliva or phlegm.

Rarely, an infected area of tissue (abscess) in the throat causes a sore throat. Another rare cause of a sore throat is a condition that occurs when the small cartilage "lid" that covers the windpipe swells, blocking airflow (epiglottitis). Both causes can block the airway, creating a medical emergency.

May. 07, 2013

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