Can an Allergy Cause a Sore Throat?

How to Tell If the Cause Is Allergic or Infectious

Woman suffering from sore throat. France
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If you are prone to allergies, it may be difficult to tell whether an allergy is causing your sore throat (pharyngitis) or if there is something else going on such a viral or bacterial infection.

People will use the term "sore throat" to refer to any number of medical or non-medical conditions that result in an inflamed and irritated throat. Allergies are among the possible causes, due largely to the symptoms of postnasal drip associated with allergic rhinitis (hay fever).

Allergy and Sore Throat

Persons suffering from allergic rhinitis will typically experience a stuffy nose and congestion that forces them to breathe through the mouth. By doing so, the mouth and throat will begin to dry out, causing scratchiness and irritation. The symptoms can be further exacerbated by the persistent drip at the back of the throat.

Postnasal drip is caused by glands in the nose and throat that continually produce mucus (as much as two quarts per day). While the mucus is meant to moisturize nasal membranes and trap foreign matter, it can often accumulate in throat and nose during an allergy.

While infection usually doesn't occur as a result of a postnasal drip, the tonsils and other tissue can often become severely inflamed. Even if they don't, a person may feel as if there is a lump in the back of the throat whenever he or she swallows.

The treatment of allergic rhinitis may involve the use of:

Non-Allergic Causes

Post-nasal drip can also be caused by non-allergic rhinitis and sinusitis (sinus infection). Other non-allergic causes include weather changes (particularly cold weather), low humidity, exposure to strong scents, and certain medications used to treat high blood pressure.

Even some of the older antihistamines used to treat an allergy can cause throat irritation including Benedryl or any formulation containing its active ingredient, diphenhydramine.

Colds can often be mistaken for an allergy since both have many of the same symptoms, including a sore throat and congestion. However, while symptoms of a cold with typically resolve within a week or two, allergies tend to persist.

Frequent morning sore throats may also be related to gastroesophageal reflux during which stomach acids can back up into the throat at night, causing irritation.

Throat Infections

Pharyngitis can also be caused by viral or bacterial infections such as streptococcus or mononucleosis. Symptoms can include painful swallowing, inflammation of the throat or tonsils, and tender lymph nodes in the neck.

Unlike allergic rhinitis, throat infections will be typically accompanied by fever, chills, and body aches. Bacterial infections such as strep throat are routinely treated with antibiotics such as penicillin or Amoxil (amoxicillin). Viral infections, a more common cause of an infectious sore throat, are typically treated with antivirals such as Tamiflu (oseltamivir) or Zovirax (acyclovir).

Sources:

Gore, J. "Acute Pharyngitis." JAAPA. 2013; 26(2):57-8.

Renner, B.; Mueller, C. and Shepherd, A. "Environmental and non-infectious factors in the etiology of pharyngitis (sore throat)." Inflamm Res. 2012; 61(10):1041-52. DOI: 10.1007/s00011-012-0540-9.