Pain, irritation, scratchiness, and swelling are common symptoms of a sore throat. Allergies, common colds, the flu, and other respiratory infections can all cause a sore throat.

Knowing what has caused a sore throat allows a person to treat it more effectively. Sore throats due to allergies, colds, and the flu generally respond well to home treatment. However, when someone has mononucleosis, tonsillitis, or a more severe case of the flu, a sore throat may require medication.

In this article, we describe how to tell whether a sore throat is due to an allergy (which is not an infection) or a viral upper respiratory infection, such as the common cold or the flu. We also cover the treatment and prevention of allergy symptoms and when to see a doctor.

man holding his throat due to a sore throat
Colds, allergies, and the flu can all cause a sore throat.

Many conditions can cause a sore throat, including common colds, the flu, and allergies, such as hay fever.

Taking note of other symptoms that appear along with a sore throat can help people get a better idea of the underlying cause.

Symptoms common to both colds and allergies include:

  • a runny or stuffy nose
  • fatigue
  • coughing and sneezing

Symptoms of colds, the flu, and infections:

  • fevers can occur with colds and the flu but not with allergies
  • muscle and body aches do not usually occur with allergies
  • swollen lymph nodes in the neck region typically indicate an infection not an allergy

Symptoms of allergies include:

  • itchy, watery eyes are common symptoms of allergies, but not of colds or the flu

An important clue to whether the cause is a cold, flu, or an allergy is how long the sore throat lasts. Colds and the flu do not usually last longer than .

However, allergies can last for as long as a person remains exposed to the allergen. For people with hay fever, allergy symptoms may last for around during pollen seasons.

Some people with hay fever may develop oral allergy syndrome after eating certain foods. Raw fruits, vegetables, and some tree nuts contain proteins that are similar to the pollens that trigger hay fever symptoms.

Oral allergy syndrome can cause:

  • an itchy mouth
  • a scratchy, irritated throat
  • redness and swelling of the lips and mouth
  • general hay fever symptoms

People who experience a sore throat or other symptoms after eating raw fruits or vegetables should speak to a doctor or allergist.

Allergies are very common. According to the , more than 50 million people in the United States have some type of allergy.

reveals that 15% of people in the U.S. have received a diagnosis of allergic rhinitis from their doctor, and up to 30% of the population have self-reported that they have nasal allergy symptoms.