A peritonsillar abscess is a pocket of pus that forms next to a tonsil, usually as a complication of a throat infection. It can cause severe one-sided throat pain and may interfere with swallowing or breathing. Prompt medical assessment is important.
Symptoms
Symptoms often become more severe on one side of the throat and may include:
- severe or worsening sore throat
- fever
- difficulty or pain when swallowing
- difficulty swallowing saliva or drooling
- a muffled or changed voice
- difficulty opening the mouth fully
- swelling around one tonsil or the soft palate
- ear pain on the affected side
- swollen or tender neck glands
Causes
A peritonsillar abscess usually develops when infection spreads into tissue beside a tonsil. Several bacteria may be involved. It can occur after tonsillitis or another throat infection.
Diagnosis and treatment
A healthcare professional usually diagnoses the condition by examining the mouth and throat. Additional tests or imaging may occasionally be needed if the diagnosis is uncertain or a deeper neck infection is suspected.
Treatment commonly involves antibiotics and drainage of the abscess with a needle or small incision. Pain relief and fluids may also be needed. Recurrent episodes may lead to discussion about tonsil surgery in selected patients.
When to get urgent help
Seek urgent medical care if a peritonsillar abscess is suspected, especially with severe one-sided throat pain, increasing swelling, difficulty opening the mouth or difficulty swallowing saliva.
Contact local emergency services immediately for difficulty breathing, rapidly worsening throat or neck swelling, severe weakness, confusion or other signs of a life-threatening illness.
After treatment
Take prescribed medication exactly as directed and complete an antibiotic course unless your healthcare professional tells you otherwise. Drink enough fluids if you can swallow safely and follow the treatment team’s instructions about pain relief and follow-up.
This information is general and does not replace individual medical assessment or treatment.
Sources and further reading
Last reviewed: 28 September 2026.