Noticing that one tonsil appears larger or feels more inflamed than the other can be a source of concern. The tonsils, located at the back of the throat, are part of the body’s immune system, acting as a first line of defense against inhaled or ingested pathogens. When one tonsil swells, it indicates a localized response to various factors, ranging from common infections to less frequent, more serious conditions. Understanding the potential reasons behind this unilateral swelling is important for appropriate self-care and knowing when to seek medical advice.
Common Reasons for Unilateral Swelling
Unilateral tonsil swelling often stems from common infections or irritations, where one side of the throat reacts more prominently. Bacterial infections, such as strep throat caused by Streptococcus pyogenes, can sometimes present with more pronounced inflammation on one tonsil. The infection leads to redness, swelling, and sometimes white patches or streaks of pus on the affected tonsil.
Viral infections, which are the most frequent cause of tonsillitis, can also contribute to unilateral swelling. Viruses like those causing the common cold, flu, or adenoviruses may lead to inflammation that affects one side more noticeably than the other. Symptoms often include a sore throat, difficulty swallowing, and general malaise.
Irritation from postnasal drip or allergies can also cause one tonsil to swell. When mucus drains down the back of the throat, it can persistently irritate one tonsil, leading to inflammation and discomfort. Minor trauma, such as scratching the tonsil with food or an object, can also induce localized swelling and pain.
More Serious Underlying Causes
While many instances of unilateral tonsil swelling are benign, certain conditions warrant closer attention due to their potential for more serious complications. A peritonsillar abscess, often referred to as quinsy, is a collection of pus that forms behind one of the tonsils, typically as a complication of bacterial tonsillitis. This condition usually presents with severe, rapidly worsening throat pain, often predominantly on one side, accompanied by difficulty swallowing, a muffled “hot potato” voice, and limited ability to open the mouth (trismus). The uvula, the fleshy part hanging at the back of the throat, may also be displaced away from the affected side.
Mononucleosis, caused by the Epstein-Barr virus (EBV), can lead to significant and often asymmetrical tonsil swelling. Along with enlarged tonsils, mono can cause extreme fatigue, fever, swollen lymph nodes in the neck, and a sore throat. The tonsil swelling in mononucleosis can appear white or gray, and may persist for several weeks or even months.
In rare instances, persistent unilateral tonsil swelling, especially in older individuals or those with risk factors like smoking and alcohol use, can be a symptom of oral cancers, such as tonsil cancer. This type of cancer might present as a painless, persistent lump or swelling on one tonsil. Other potential indicators include a chronic sore throat, difficulty swallowing, ear pain, or a lump in the neck. While less common, other rare conditions like deep neck infections or certain autoimmune processes can also cause unilateral tonsil enlargement.
When Professional Medical Help is Needed
It is important to recognize when unilateral tonsil swelling requires professional medical attention. Seek medical help if the swelling is accompanied by severe difficulty swallowing, making it painful or impossible to consume liquids or solids. Difficulty breathing or speaking, such as a muffled voice or excessive drooling, also warrants immediate evaluation.
A high fever, especially above 101°F (38.3°C), or chills alongside the swollen tonsil, indicates a more serious infection. Rapidly worsening swelling or pain suggests a quick progression that requires prompt medical assessment. Symptoms like a stiff neck, particularly when accompanied by fever, or an inability to open the mouth fully (trismus), are concerning signs that necessitate urgent medical consultation. If unilateral swelling persists for more than a few days without improvement, recurs frequently, or occurs without typical cold or flu symptoms, medical advice should be sought.
Medical Evaluation and Management
A healthcare provider will typically begin with a thorough physical examination for a unilaterally swollen tonsil. This involves visually inspecting the throat and tonsils, and often gently palpating the neck to check for swollen lymph nodes. The doctor may also assess the ability to swallow and open the mouth fully.
To pinpoint the cause, several diagnostic tests may be performed. A throat swab is common to test for bacterial infections like Group A Streptococcus, which causes strep throat. For suspected viral infections like mononucleosis, blood tests such as a Monospot test or Epstein-Barr virus (EBV) antibody test can confirm the diagnosis. If a peritonsillar abscess is suspected, imaging like a CT scan might be used to visualize the extent of the infection, especially if symptoms are severe or there’s diagnostic uncertainty.
Treatment depends on the underlying cause. Bacterial infections are typically managed with a course of antibiotics, such as penicillin or amoxicillin, often for 10 days, with alternatives like macrolides or cephalosporins for those with penicillin allergies. For viral infections, antibiotics are ineffective, and treatment focuses on supportive care, including pain relief with over-the-counter medications like ibuprofen or acetaminophen, hydration, and rest. A peritonsillar abscess usually requires drainage, which can be done through needle aspiration or incision and drainage, often followed by antibiotics. In cases of suspected malignancy or persistent issues, a referral to an ear, nose, and throat (ENT) specialist may be necessary for further investigation or potential tonsillectomy.