What could cause asymmetrical swelling of the tonsils?

Reviewed by Yoshinori Abe, MD

Internal Medicine

Asymmetrical tonsil swelling—when one tonsil is noticeably larger than the other—is most often caused by infections such as tonsillitis, strep throat, or a peritonsillar abscess. Less commonly, it can signal more serious conditions, including benign growths or tumors like lymphoma. Because the causes range from mild to serious, a medical evaluation is essential for an accurate diagnosis and timely treatment.

If you've noticed uneven tonsils, don't guess—get clarity. A free, instant, online symptom check can help you understand possible causes based on your specific symptoms and guide your next steps, whether that's monitoring at home or seeing a doctor promptly. It takes just a few minutes and could save you time, worry, and unnecessary delays in care.

Reviewed for medical accuracy: 07/20/2026

Important Next Steps

Discover likely causes of swollen tonsils See if your tonsil swelling needs care Find out if it could be serious Explore OTC options for tonsil swelling Find a doctor for tonsil problems Learn home remedies for swollen tonsils Understand if asymmetrical tonsils need checking

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Explanation

Asymmetrical swelling of the tonsils means that one tonsil is larger than the other. This can happen for a few reasons.

Infections: Often, infections such as tonsillitis can cause one tonsil to swell more than the other. This is usually due to bacteria or viruses.
Other Causes: According to Cinar, sometimes the swelling doesn't cause any symptoms but still needs to be checked. Guimarães and colleagues mention that in rare cases, a bigger tonsil might be linked to more serious conditions like tumors.
Evaluation: Cortez and others suggest that doctors should look at the tonsils carefully to find out why one is bigger. This might include checking for infections or other conditions.

If you notice one tonsil is bigger than the other, it's important to see a doctor. You can start by using a free symptom checker to help identify what might be causing your symptoms, but follow up with a healthcare professional to make sure it's nothing serious.

(References)

Cinar F. (2004). Significance of asymptomatic tonsil asymmetry. Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery, 15243564.
Guimarães AC, de Carvalho GM, Correa CR, & Gusmão RJ. (2015). Association between unilateral tonsillar enlargement and .... Critical reviews in oncology/hematology, 25487766.
Cortez EA, Mattox DE, Holt GR, & Gates GA. (1979). Unilateral tonsillar enlargement. Otolaryngology and head and neck surgery, 530694.

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