Swollen tonsils appear as enlarged, red mounds of tissue on either side of the back of your throat. Healthy tonsils are pinkish, oval-shaped, and sit relatively flat against the sides of the throat. When inflamed, they become visibly larger, redder, and may display white or yellow patches depending on the cause. The degree of swelling can range from barely noticeable to so large that the two tonsils nearly touch each other in the middle of the throat.
What Healthy Tonsils Look Like
Normal tonsils are pinkish, roughly almond-sized, and positioned symmetrically on each side of the throat. Their surface has a slightly bumpy or ridged texture, with small pits called crypts scattered across them. In some people, healthy tonsils are naturally larger or sit at slightly different depths in the throat, which can make one look bigger than the other even without any swelling. This is worth knowing so you don’t mistake your normal anatomy for a problem.
How To Check Your Own Tonsils
You can get a decent look at your tonsils with a mirror and a light source. Start by rinsing your mouth with water to clear away food particles. Stand in front of a mirror in a well-lit room, or use a phone flashlight aimed at the back of your throat. Open your mouth wide and push your tongue flat against the bottom of your mouth, or stick it straight out. Saying “aaaahh” helps flatten the tongue and open the view. Your tonsils sit on either side of the throat, just behind the arch of tissue at the back of your mouth.
Mild to Severe Swelling
Doctors grade tonsil size on a scale from 0 to 4+, based on how much of the airway the tonsils block. At grade 1+, the tonsils take up about 25% of the space between them. At grade 2+, they fill 25 to 50% of that space. Grade 3+ means they’re blocking 50 to 75%, and at grade 4+, sometimes called “kissing tonsils,” they occupy more than 75% of the airway and nearly or fully touch in the midline.
You don’t need to memorize these grades, but the scale gives you a useful frame of reference. If your tonsils are just slightly puffy and red, that’s the mild end. If they’re bulging toward each other and making it hard to swallow or breathe comfortably, that’s the severe end.
White Patches and What They Mean
The most common visual clue beyond redness is white or yellow material on the tonsil surface, but the cause matters. Different conditions produce distinct patterns.
Strep Throat
Strep produces white pus that collects on or around the tonsils. The throat looks intensely red, and you may also notice small red dots (called petechiae) on the roof of the mouth. These red dots are one of the more reliable visual hints that the infection is bacterial rather than viral. Strep typically does not come with a runny nose, cough, or hoarse voice, so a very red throat with white patches but few cold symptoms is a classic strep presentation.
Viral Infections
Most sore throats are viral, and they tend to cause general redness and rawness across the back of the throat without the concentrated white patches you see with strep. The exception is mononucleosis (mono), caused by the Epstein-Barr virus. Mono can produce heavy white or grayish coating on the tonsils that looks strikingly similar to strep. The tonsils with mono are often dramatically swollen, sometimes to grade 3+ or 4+. Because mono and strep look so alike, a throat swab or blood test is the only reliable way to tell them apart.
Tonsil Stones
Not every white spot on a tonsil means infection. Tonsil stones are small, pebble-like lumps that form inside the crypts of the tonsils. They look like tiny white or yellow bits embedded in the tonsil surface. Unlike the patchy, spreadable coating of an infection, tonsil stones are discrete, solid-looking pieces. You might have one or several. They’re usually small and harmless, though they can cause bad breath and a mild sensation of something being stuck in your throat. They don’t come with fever, and the surrounding tissue generally isn’t red or inflamed.
One Tonsil Bigger Than the Other
Seeing one tonsil noticeably larger than the other can be alarming, but it’s usually not serious. The most common causes are a one-sided infection, benign swelling, or simply a difference in how deep each tonsil sits in its pocket of tissue. A retrospective analysis published in the Annals of the Royal College of Surgeons found that apparent asymmetry is often just an artifact of anatomy and assessment angle rather than true enlargement.
That said, there are situations where one-sided swelling deserves prompt attention. A peritonsillar abscess, a pocket of pus that forms beside the tonsil, causes dramatic one-sided swelling along with severe pain, difficulty opening the mouth, and sometimes a muffled or “hot potato” voice. In rare cases, a tonsil that grows rapidly on one side, especially alongside neck lumps, unexplained weight loss, or persistent fatigue, warrants evaluation to rule out lymphoma. These serious causes are typically accompanied by a visibly abnormal tonsil surface and systemic symptoms, not just size difference alone.
What Each Visual Clue Suggests
- Red and swollen, no patches: Most likely a common viral infection or general irritation.
- Red with white pus and red dots on the palate: Strongly suggests strep throat.
- Massively swollen with a thick white or gray coating: Could be mono, especially with extreme fatigue and swollen neck glands.
- Small white or yellow solid bits lodged in the surface: Tonsil stones, generally harmless.
- One tonsil much larger with severe pain and trouble opening the mouth: Possible peritonsillar abscess, which needs prompt care.
When Swelling Changes Over Time
Viral tonsil swelling typically peaks within the first two to three days and starts improving within a week. Strep throat responds quickly to antibiotics, with noticeable improvement in swelling and pain within 24 to 48 hours of starting treatment. Mono is the outlier: tonsil swelling from mono can persist for two to four weeks, and the fatigue may linger even longer.
If your tonsils stay swollen for more than two weeks without improvement, or if swelling keeps returning several times a year, that pattern itself is useful information to bring to a clinician. Chronic or recurrent tonsil swelling sometimes leads to a conversation about whether the tonsils are causing more problems than they’re solving.