Quinsy is an inflammation of the tonsils and surrounding tissues in the throat. It is also known as peritonsillar abscess and typically occurs as a complication of untreated strep throat or tonsillitis. The symptoms of quinsy include severe throat pain, difficulty swallowing, and fever. It requires prompt medical treatment as it can lead to serious complications if left untreated. Treatment usually involves antibiotics and drainage of the abscess if necessary.