How can you tell if your tonsillitis is viral or bacterial, and does that change how contagious it is?

Tonsillitis can be caused by either a virus or bacteria, and identifying the type matters because it affects how contagious the infection is and how it should be treated. Bacterial tonsillitis, most often caused by group A streptococcus, typically requires antibiotics to resolve and prevent complications. Viral tonsillitis, however, usually clears on its own without antibiotics and is managed with rest, fluids, and symptom relief.

Because the symptoms of viral and bacterial tonsillitis can look nearly identical—sore throat, swollen tonsils, fever, and difficulty swallowing—it's difficult to tell them apart without guidance. Taking a free, instant, online symptom check can help you better understand what may be causing your symptoms and decide whether home care is enough or if you should see a doctor. It's a fast, private way to clarify your next steps before your condition worsens or spreads to others.

Reviewed for medical accuracy: 07/20/2026