Sore Throat on One Side: 8 Common Causes and When It Is Serious

Written by Naurah Gaspard, DNP, FNP-C, FNP-BC · Medically reviewed by Cherlie Joseph, MSN, FNP-BC · Updated November 2026

A sore throat on one side is most often caused by something minor, like postnasal drip draining down one side, a swollen lymph node, a small sore or a nearby tooth or ear problem. The one-sided cause that needs urgent attention is a peritonsillar abscess, which brings severe pain, trouble opening the mouth, drooling and a muffled voice. A one-sided sore throat that lasts longer than 2 to 3 weeks should be checked in person.

Why a sore throat can hurt on just one side

Your throat has two sides, each with its own tonsil, lymph nodes and nerves. Infections often start on one side before spreading, and many "neighbors" of the throat, such as the teeth, ears, jaw and sinuses, share nerve pathways with it. Pain from those areas can feel like it is coming from your throat. That is why one-sided throat pain is common, and why the cause is often not in the throat at all.

8 common causes at a glance

Cause	Clues
Postnasal drip (cold, allergies, sinusitis)	Worse in the morning, stuffy nose, throat clearing; often on the side you sleep on
Swollen lymph node	Tender lump under the jaw on the sore side during or after a cold
Viral pharyngitis or early tonsillitis	Starts on one side, may spread to both within a day or two
Strep throat	Sudden pain, fever, swollen tonsils, no cough; needs a test
Canker sore or small injury	Sharp spot of pain after a chip, hot food or fish bone
Tonsil stones	White lump on one tonsil, bad breath, feeling something is stuck
Tooth or wisdom tooth infection	Jaw or gum pain, sensitivity to hot or cold, swelling near a back tooth
Ear infection or acid reflux	Ear fullness or pain; or heartburn, sour taste and hoarseness in the morning

Many of these settle in a few days. If you also have cough and congestion, a cold is the likely culprit; our guide to strep vs. viral sore throat explains when a strep test makes sense.

The serious one: peritonsillar abscess

A peritonsillar abscess is a collection of pus next to one tonsil, usually after tonsillitis. MedlinePlus notes it is most common in teens and young adults. Signs include:

• Severe throat pain, usually on one side, often with ear pain on that side
• Trouble opening your mouth fully
• Trouble swallowing, or drooling because swallowing hurts
• A muffled, "hot potato" voice
• Fever, chills and swelling of the face or neck

An abscess usually needs to be drained by a clinician, along with antibiotics. Swelling can spread and threaten the airway, so this is not a wait-and-see situation. If your throat pain is getting worse on one side despite treatment for strep or tonsillitis, get seen in person the same day.

What helps at home

• Pain relief: acetaminophen or ibuprofen, used as directed on the label.
• Salt-water gargles: about half a teaspoon of salt in a cup of warm water, several times a day.
• Postnasal drip: saline rinses, a humidifier, and, if allergies are the trigger, an over-the-counter antihistamine or steroid nasal spray. Sleeping with your head slightly raised can help.
• Reflux: avoid eating within 2 to 3 hours of bed, limit late-night alcohol, spicy and fatty foods, and raise the head of the bed.
• Tonsil stones: gargling after meals and good oral hygiene; do not poke at them with sharp objects.
• Tooth pain: see a dentist promptly. A tooth infection will not clear with throat remedies.

More soothing ideas are in our sore throat remedies guide.

When a one-sided sore throat needs a closer look

A sore throat that hangs on is different from one that comes with a cold. The National Cancer Institute lists a sore throat that does not go away, trouble swallowing, ear pain, a lump in the neck and voice changes as possible signs of head and neck cancer. These symptoms are far more often caused by something harmless, but they deserve an exam by a provider, often with a referral to an ear, nose and throat (ENT) specialist, if they last more than 2 to 3 weeks. That is especially true if you smoke or have smoked, drink alcohol heavily, or have a history of HPV.

Also get checked if one-sided throat pain keeps coming back, if you have a neck lump that is not shrinking after a few weeks, or if you have unexplained weight loss or are coughing up blood.

Frequently asked questions

Is a sore throat on one side strep?

It can be, but strep usually affects both sides of the throat. One-sided pain is more often from postnasal drip, a swollen lymph node, a small sore or a tooth or ear problem. A strep test is the only way to know.

Why does my throat hurt on one side when I swallow?

Common reasons include a swollen tonsil or lymph node on that side, a canker sore or scratch, or drainage from your sinuses. Severe pain with trouble opening your mouth or drooling can be an abscess and needs prompt care.

Can a tooth infection cause a sore throat on one side?

Yes. Infections of the back teeth, especially wisdom teeth, can cause pain in the throat, jaw and ear on the same side. A dentist should evaluate it.

Sources

• MedlinePlus: Peritonsillar abscess
• MedlinePlus: Sore throat
• National Cancer Institute: Head and Neck Cancers

Keep reading

• Tonsillitis in adults
• Strep throat treatment for adults
• Sinus infection or Florida allergies?
• Browse all conditions and treatments A to Z

This article is for general education and is not a substitute for medical advice. Treatment, including any prescription, is decided by a licensed provider after reviewing your health history. OurTopClinic is not for emergencies; if you have a medical emergency, call 911. OurTopClinic serves adults located in Florida, New Mexico, Oregon and Washington. Learn more at ourtopclinic.com.