- Causes of a sore throat on one side includes the flu, tonsillitis, a canker sore, or a tumor.
- Look out for other symptoms to help you identify what's causing your sore throat on one side.
- If you're having trouble breathing or swallowing, see a doctor for a diagnosis and treatment.
Waking up with a tickle in your throat could be a telltale sign you're getting sick. But sometimes the soreness may happen on only one side. That can mean something as minor as a cold or more severe like a tumor.
Here are eight medical conditions that can cause a sore throat on just one side and how to treat each case.
1. A cold or the flu
A viral infection, like a cold or the flu, can cause lymph nodes on one side of your neck to swell, triggering pain on that side of the throat, says Dr. Sabina Rebis, a primary-care doctor for Northeast Medical Group Internal Medicine.
Diagnosis: Symptoms of a cold or flu can be similar, but some key signs you may have the flu include a high fever of 102 degrees Fahrenheit, body aches, and chills. A cold, on the other hand, will typically involve a sore throat, stuffy nose, and sneezing.
Treatment: A sore throat from an infection like a cold or the flu typically takes up to 10 days to resolve on its own. To help your throat heal, try drinking warm fluids, taking a hot shower, and gargling saltwater.
2. COVID-19
A sore throat is one of many COVID-19 symptoms, and just like any other viral infection it can trigger swollen lymph nodes and postnasal drip that can cause soreness on one side of the throat, Rebis says.
Diagnosis: The best way to determine whether you have COVID-19 is to take a coronavirus test. Antigen tests, aka rapid tests, can be purchased at your local pharmacy and performed at home. They are less accurate than molecular tests, in which the results are sent to a laboratory for analysis. Since the US declared an end to the public health emergency on May 11, 2023, COVID-19 tests aren't free anymore. Some insurance companies may still choose to cover at-home or molecular tests, but they don't have to, so you may need to pay for tests out-of-pocket.
Treatment: Treatment for a sore throat from COVID-19 is similar to treatment for the flu. This includes:
- Taking lozenges or other cough medicine
- Adding a teaspoon of honey to your hot tea or water
- Drinking fluids throughout the day
- Eating a popsicle or sorbet if your throat is irritated from coughing
- Taking the antiviral Paxlovid if you are eligible and your doctor determines it would be a good treatment option
3. Tonsillitis
Tonsillitis occurs when your tonsils become inflamed and swollen and is typically more common in children than in adults. About 70% of cases of tonsillitis are from a virus such as the flu virus. But bacteria can also be the culprit.
If you feel pain on only one side of your throat, it may mean only one of your tonsils is infected.
Diagnosis: Symptoms characteristic of tonsillitis are white patches or redness at the back of your throat where your tonsils are found.
Treatment: Your doctor can prescribe antibiotics to get rid of tonsillitis caused by a bacterial infection. But if tonsillitis is from a viral infection, you may need to wait for it to pass on its own meanwhile soothing your sore throat with the following strategies:
- Gargling salt water by mixing half a teaspoon of salt with 8 ounces of warm water
- Place a humidifier in your bedroom to keep the air moist. Adding 1 or 2 tablespoons of vapo rub or hydrogen peroxide solution may relieve your throat further.
- Taking lozenges
- Drinking warm liquids
4. Canker sores
Canker sores are small shallow wounds that usually form around the mouth but can also sometimes appear in the back of the throat, near the tonsils, says Dr. Omid Mehdizadeh, an otolaryngologist and laryngologist at Providence Saint John's Health Center.
If a canker sore forms on or near your tonsils, it can cause severe sore throats. And if it's on only one tonsil, that can lead to a sore throat on one side.
Causes of canker sores include:
- Mouth injury
- Deficiency in vitamin B12, zinc, folic acid, or iron
- Eating spicy or acidic food
- Toothpaste with sodium lauryl sulfate
Diagnosis: A canker sore appears as a half-inch to 1-inch white-yellowish ulcer with surrounding redness. Canker sores are painful when eating or talking.
Treatment: "Typically, the treatment for canker sores [revolves around] pain control and hydration. Occasionally, topical medications can help soothe the area," Mehdizadeh said.
You can reduce the pain by taking over-the-counter pain relievers and rinsing your mouth with either saltwater or mouthwash without alcohol.
The pain from a canker sore should resolve in a few days, while the ulcer itself will take one to two weeks to disappear.
5. GERD
Gastroesophageal reflux disease is a chronic disease that affects about 20% of Americans. It occurs when stomach acid travels back up through the esophagus, triggering symptoms such as heartburn, chest pain, and occasionally a sore throat on one side, depending on how you sleep.
"Sometimes the sleep position we're in can make stomach acid travel a little bit farther up in our esophagus. Microscopic droplets can actually irritate the back of the throat without us actually knowing it because we don't feel it when we sleep," Rebis says.
While Rebis explains that GERD commonly happens on both sides of the throat, it is possible to irritate just one side if you tend to sleep mainly on one side.
Treatment: To prevent acid reflux during sleep, Rebis recommends elevating the head of the bed at least 6 to 8 inches using bed risers. Other options include elevating your shoulder blades when sleeping, stopping meals 2 hours before bed, and limiting chocolate, coffee, and alcohol late at night. For immediate relief, your doctor may prescribe Protonix or Pepcid or you may try over-the-counter medications such as Tums or Rolaids.
6. Peritonsillar abscess
Peritonsillar abscess is a pus-filled nodule of bacteria and cellular debris found near the tonsils. If the pus collects on one side, it can cause soreness on that side of the throat.
Diagnosis: Doctors may provide a diagnosis of peritonsillar abscess if they see swelling on the roof of your mouth as well as one side of your throat. In addition to a sore throat, symptoms include:
- Feeling feverish
- Difficulty talking
- Difficulty swallowing
Treatment: An abscess may grow large enough that it can obstruct your airways making it harder to breathe. Therefore, if you think you have a peritonsillar abscess, you should see a doctor who will use a needle to drain the pus.
Draining the pus should clear up your symptoms and give you instant relief. Your doctor may prescribe antibiotics after drainage to ensure the infection doesn't spread.
7. Laryngitis
Laryngitis is when your voice box becomes inflamed typically because of a viral or bacterial infection. But smoking, vaping, a dry cough, and dehydration can also cause the condition.
If your laryngitis is due to an infection, then swollen lymph nodes on one side of your neck and a heavy postnasal drip to one side can cause a sore throat on that same side.
Diagnosis: A hallmark feature of laryngitis is losing your voice or a change in your voice. Beyond irritated or swollen vocal cords, laryngitis can make it hard to swallow and make it painful to speak. You might also feel a scratchy or dryness in the back of your throat.
Treatment: Laryngitis should go away on its own after two weeks. During that time, you can soothe an irritated sore throat by drinking plenty of fluids, taking a cough suppressant, and turning on the humidifier in your room. If your symptoms last longer than 2 weeks, see a doctor as it may be a sign of something serious like nerve damage or cancer.
8. Tumor
If a tumor is growing on one side of your throat, it can cause pain on just that one side, Mehdizadeh says. In fact, one of the first signs of throat cancer is a sore throat.
Diagnosis: The only way to diagnose, or rule out, a tumor is to see a doctor who can check for any growing lumps or other symptoms. A doctor can also perform a laryngoscopy, in which a small camera is inserted through the nose or mouth to look for polyps, tumors, or other signs of inflamed growths inside your larynx and hypopharynx.
Treatment: For immediate relief, you can try pain medication. However, your doctor may decide that you need surgery to remove the tumor depending on factors including its size and growth. If the tumor was cancerous, radiation therapy or chemotherapy may be necessary to prevent it from coming back.
When to see a doctor
Mehdizadeh says there's no urgent need to see a doctor if your sore throat lasts less than five days and there's no significant changes in breathing, swallowing, or neck swelling.
"Just keep an eye on it. Staying hydrated and taking pain medications as needed is generally advisable," Mehdizadeh says.
If your sore throat lasts longer than five days or worsens over the five-day period, he advises seeking further care to rule out a bacterial infection that may need antibiotics or something more serious like a tumor.
Insider's takeaway
Sore throats on one side have numerous causes, with viral infections being the most common.
Many sore throats are manageable at home with warm liquids, taking over-the-counter pain relievers, and breathing in steam to reduce swelling and pain.
"Sore throats on one side are common and it's important not to be nervous about them. But if you find it worsening, it's important to see your doctor and get that evaluated," Rebis says.