If you frequently head to your doctor for a sore throat, it most probably happens due to the cold, flu, or allergies. There’s no doubt that a sore throat can give you painful sensations, but it’s not something to be afraid of. However, a sore throat on one side can indicate a serious illness.

Let’s take a look at eleven potential causes of a sore throat on one side.

1. Postnasal drip

During nasal congestion, mucus and fluid drain down the backside of the throat. This is called postnasal drip. If the drainage continues for a long period of time, the throat can become painful, and you may feel scratchiness and soreness.

The drainage can irritate a particular part of your throat more than others. You may experience inflammation and pain on one side of the throat.

Antibiotics do not affect viral illnesses. Resting and taking plenty of fluids is the best way to treat a sore throat caused by a cold, flu, or any other viral illness.

2. Swollen lymph nodes

The lymph nodes of your body trap the viruses and bacteria before they can enter and affect the other parts of the body. This process causes the lymph nodes to become swollen and sore.

The lymph nodes nearest to the throat lie on each side. Inflammation of these nodes can make your throat feel sore and irritated.

Several infections and diseases cause swollen lymph nodes. In some cases, soreness happens in a single node, causing a sore throat on one side.

Some conditions resulting in inflamed lymph nodes include:

  • strep throat
  • an ear infection
  • a cold or flu
  • tooth infection
  • mononucleosis
  • skin infection

3. Tonsillitis

Tonsillitis is the swelling of your tonsils due to an infection. There are two tonsils, one on each side of your throat. Sometimes, only a single tonsil is affected by tonsillitis, causing a sore throat on one side.

The primary cause of viral infection is tonsillitis, but they can also occur due to bacterial infections. Sore throat is the main symptom, accompanied by:

  • fever
  • bad breath
  • a runny nose
  • nasal congestion
  • inflamed tonsils with pus patches
  • swollen lymph nodes
  • difficulty swallowing

Viral tonsillitis usually gets better on its own within a week or so. OTC pain relievers and saltwater gargles can help soothe the pain. For bacterial tonsillitis, your doctor will recommend antibiotics.

4. A tooth abscess or infection

A tooth abscess is an accumulation of pus due to a bacterial infection. This pus collection grows at the tip of the tooth’s root. The most common symptoms are excruciating pain that travels to the jawbone and to the ear on the side of the face. The lymph nodes close to the neck and throat can also become inflamed and sore.

Other signs that your tooth is infected include:

  • sensitivity to hot and cold temperatures
  • pain while chewing
  • fever
  • swelling in your face or cheek
  • tender, swollen lymph nodes under your jaw or in your neck

If your wisdom teeth erupt abnormally, there are high chances that infection may develop. Even with a normal eruption, it’s difficult to clean the third molars thoroughly, and an infection can develop due to poor hygiene. Infection in the wisdom teeth can result in jaw pain and inflammation, and you may find it hard to open the mouth.

If your wisdom teeth are causing problems, your dentist will likely recommend removing them. If you have a tooth abscess, your dentist may make an incision to drain the pus. You might also need an antibiotic.

The best course of treatment would be to schedule an appointment with your dentist, who might recommend a root canal to get rid of the pus or extract the impacted wisdom teeth.

In the meantime, you can try the following home remedies to ease the pain due to tooth infection.

5. Throat injury

An injury to the back of the mouth or throat can happen due to many reasons such as:

  • eating hard or sharp foods like chips or crackers
  • burns from eating or drinking something hot
  • endotracheal intubation that aids breathing

Gargling with warm salty water can help minimize symptoms if one side of the throat is sore from scraping or burning.


In this condition, the stomach contents, including the stomach acid, drive up in the throat and food pipe.

Laying down can worsen GERD. If the stomach acid backs up while laying down, your throat may become sore on one side.

7. Peritonsillar abscess

When tonsillitis is left untreated or worsens, it causes a peritonsillar abscess in the tissues surrounding the tonsils. You may experience severe pain and tenderness on one side of the throat. Other symptoms include:

  • fever
  • difficulty swallowing
  • swollen lymph nodes

If you have this condition, immediately seek medical help. If things turn severe, you may find it hard to breathe. Your doctor may drain the abscess or prescribe antibiotics for the infection. 

8. Hand, foot, and mouth disease

This viral disease results in sores on the feet, hands, and mouth. Sores can appear at the backside of your mouth and close to the sides of the throat. When the throat is affected, one side may become worse than the other.

This illness usually affects children aged 5 years or younger; however, it can also develop in adults.

OTC pain relievers, drinking plenty of fluids, and resting are the keys to combating this disease.

9. Inflammation of the larynx

Overusing your voice, a viral infection, or irritation can cause swelling in your voice box – called laryngitis.

Your voice box consists of two vocal cords. When these cords are irritated or become inflamed, you may experience pain and a change in your voice. When one cord is sorer than the other, you may feel pain on only one side of the throat.