Causes and Risk Factors of Sore Throat

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Common causes of a sore throat include infections, allergens, cancer, cigarette smoke, and dry air. Even the simple act of shouting or singing loudly can injure your throat, causing pain and inflammation. And sometimes, seemingly unrelated health issues, such as acid reflux, can also cause a sore throat. 

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Common Causes

The pharynx is the cavity behind the nose and mouth that leads to your stomach and lungs. It is a common target for infection and irritation that cause a sore throat.

You might know the cause of your sore throat, either because of an accompanying symptom or an injury, but sometimes you may need to see a healthcare professional for a diagnosis. Here are the most typical causes of a sore throat, ranging from minor, localized infections to more serious, systemic disease:

Viral Infections

Viral infection accounts for more than half of all pharyngitis cases, and the common cold—caused by more than 200 types of virus, including adenoviruses, rhinoviruses, and coronaviruses—leads the way. 

A sore throat caused by a viral infection is often accompanied by nasal congestion, sneezing, runny nose, headache, and fever.

Tonsillitis can also develop.

Other viral infections associated with pharyngitis include:

  • Orthomyxovirus, a family of influenza viruses
  • Infectious mononucleosis, caused by the Epstein-Barr virus
  • Coxsackievirus and echovirus, causing blisters in the mouth and throat and herpangina pain in young children
  • Measles virus (proper vaccination can help prevent this)
  • Herpes simplex virus (HSV), which can cause an ulcerous lesion in the throat
  • HIV: Sore throat and other flu-like symptoms can arise early in the infection. Later, sore throat may accompany secondary infections, such as cytomegalovirus and fungal infections.

While certain viral infections, like HSV, can be treated with antiviral drugs, many others (including measles, mononucleosis, and the common cold) don't have a cure and often resolve on their own.

Bacterial Infections

A number of bacterial infections can cause a sore throat. One of the most common is Streptococcus pyogenes, the bacteria associated with strep throat (streptococcal pharyngitis). It is thought to account for 10% of sore throats in adults and young children, and up to a third of sore throats in school-age children.

Strep throat is relatively minor, but can sometimes lead to more severe infections or complications. Strep does not cause respiratory symptoms like a cough and congestion.

Symptoms of strep throat can include fever, nausea, vomiting, bad breath, and visible inflammation of the throat.

Less common bacterial throat infections include:

  • Neisseria gonorrhoeae (gonorrhea)
  • Bordetella pertussis (whooping cough)
  • Bacterial tonsillitis
  • Bacterial pneumonia

A rapid strep test can screen for strep throat. A throat culture can identify or help rule out a bacterial cause. Antibiotic treatment is based on which bacteria is found.

Fungal Infections

The most common cause of fungal throat infections is Candida albicans, a type of yeast that causes oral thrush and yeast infection. Infection tends to occur in people who have a suppressed immune system, with the most severe cases often associated with advanced HIV infection. Other risks include inhaled steroids, wearing dentures, or uncontrolled diabetes.

Oral thrush (oral candidiasis) often doesn't cause symptoms. In some cases, it can lead to soreness of the mouth, tongue, and throat. When it involves the esophagus, candidiasis is considered serious. Fungal infections like these are treated with antifungal medications.

Allergic Pharyngitis and Postnasal Drip

Allergic pharyngitis is throat inflammation caused primarily by an allergen that enters the nose or mouth. You may experience this when your nose is stuffed up due to seasonal allergies, forcing you to breathe through your mouth. The tissues dry out, causing a scratchy feeling and irritation.

You may also have postnasal drip as mucus drains from your nasal passages down the back of your throat. This can lead to inflammation of the throat and tonsils if the mucus is infected. Or, you may feel like you have a lump in the back of your throat.

Acid Reflux and GERD

Acid reflux occurs when stomach acid or bile backs up toward the throat. These digestive fluids are irritating to the mucosal lining of the pharynx and esophagus and can cause a sore throat, particularly when you wake up in the morning or after you've been lying down for a while.

Acid reflux occurs for many reasons, including failure of the lower esophageal sphincter (LES) to close or a hiatal hernia.

While acid reflux may be the direct result of something you've had to eat or drink, it may also be a persistent condition referred to as gastroesophageal reflux disease (GERD). When stomach acid frequently gets up to the throat, this is called laryngopharyngeal reflux. Laryngopharyngeal reflux can also cause symptoms of a cough, throat clearing, and a feeling like there is something stuck in the throat, or hoarseness.

Other Couses

Other possible causes of pharyngitis include:

  • Mouth breathing, especially when sleeping
  • Direct throat injury from ingesting hot liquids or chemicals, or trauma to the throat
  • Throat surgery or airway intubation during any type of surgery can cause trauma, with inflammation during healing
  • Muscle strain caused by talking loudly or for long periods of time
  • Benign vocal lesions caused by overuse or trauma to vocal cords
  • Epiglottitis (inflammation of the cover of the windpipe)
  • Peritonsillar abscess (a complication of tonsillitis)
  • Throat cancer
  • Antipsychotics and other drugs (such as pramipexole used to treat Parkinson's)

There is no known genetic component for the risk of sore throat, although there may be a genetic predisposition to GERD.

Lifestyle Risk Factors

Certain risk factors for a sore throat, like your body's reaction to an allergen, are out of your control. But here are some that you can have some influence over.

Irritants and Toxins

Exposure to certain substances can cause direct inflammation of the pharynx and associated organs. This can include inhaled irritants like air pollution, cigarette smoke, and industrial fumes.

Irritation can also be caused by foods and other substances you ingest, such as alcohol, spicy foods, or chewing tobacco. 

Dry air and a lack of humidity can leave your throat feeling dry and scratchy.

This is common in arid climates. Both hot air and excessive air conditioner use can also cause throat irritation.


Infrequent hand washing makes it easier for you to contract illnesses related to germs you may pick up over the course of your day, including those that raise your risk of respiratory infection and sore throat.

Flu Vaccination

Getting an annual shot can help reduce your risk of influenza.


Strep throat and colds can easily spread in places where large numbers of people interact, particularly in close quarters, such as military training facilities or college dorms. 

According to the CDC, school children and those in daycare centers are prone to colds and the spread of strep throat due to being in groups with other children. Parents may also catch these infections from their kids. 

While you may not always be able to avoid this kind of exposure, knowing the risk can help remind you to be diligent about practices that can help you avoid catching illnesses (especially during peak seasons), like hand washing and avoiding drinking fountains.

Use of Your Voice

You may also be prone to a sore throat if you strain your vocal cords and throat muscles by yelling, talking loudly, or singing for long periods of time.

Frequently Asked Questions

  • Am I more likely to get a sore throat during pregnancy?

    Yes. Changes in your immune system during pregnancy make you more susceptible to infections that cause a sore throat. You’re also more likely to experience heartburn and GERD, in which stomach acids irritate the throat.

  • What causes of a chronic sore throat?

    A chronic sore throat, defined as throat pain that lasts more than 12 weeks despite medication, can be caused by many conditions. The most common are tonsillitis, GERD, inflammation of the submandibular gland, and laryngopharyngeal reflux.

    A sore throat lasting more than 2 weeks should always be evaluated by a healthcare provider because it can be a sign of cancer.

  • Can thyroid problems cause a sore throat?

    Yes. If your thyroid is enlarged, forming a goiter, it can cause a sore throat. Viral infections of the thyroid may also bring on pain. In rare instances, subacute thyroiditis, which is caused by a viral infection, can also cause throat pain and difficulty swallowing.

9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Centers for Disease Control and Prevention. Strep Throat: All You Need to Know

  3. Centers for Disease Control and Prevention. Fungal Diseases. Candida infections of the mouth, throat, and esophagus

  4. Icahn School of Medicine at Mount Sinai. Inside. Could Your Sore Throat Be Caused by Acid Reflux?

  5. Centers for Disease Control and Prevention. Sore Throat

  6. Centers for Disease Control and Prevention. Pharyngitis (Strep Throat)

  7. Adar T, Grisaru-Granovsky S, Ben Ya’acov A, Goldin E, Bar-Gil Shitrit A. Pregnancy and the immune system: general overview and the gastroenterological perspective. Dig Dis Sci. 2015;60(9):2581-2589. doi:10.1007/s10620-015-3683-z

  8. Kundu S, Dutta M, Adhikary BK, Ghosh B. Encountering chronic sore throat: How challenging is it for the otolaryngologists? Indian J Otolaryngol Head Neck Surg. 2019;71(S1):176-181. doi:10.1007%2Fs12070-017-1191-5

  9. MedlinePlus. Subacute thyroiditis.

Additional Reading

By Kristin Hayes, RN
Kristin Hayes, RN, is a registered nurse specializing in ear, nose, and throat disorders for both adults and children.