Tonsillar/Peritonsillar infections include uncomplicated tonsillitis, peritonsillar cellulitis, intratonsillar abscess and peritonsillar abscess, conditions with similar clinical presentations.

Peritonsillar abscess, the most common deep space neck infection, particularly in children and adolescents, can have life-threatening complications if not diagnosed and treated promptly, such as sudden rupture with aspiration, extension of the infection into the mediastinum, acute airway obstruction and/or sepsis.

The formation of an abscess usually begins as a superficial infection or acute tonsillitis that progresses to a peritonsillar cellulitis and further to a peritonsillar abscess.

The distinction between tonsillar inflammation and peritonsillar abscesses can be difficult based on clinical findings, due to similarities in symptoms and signs. These patients typically complain about unilateral sore throat, otalgia, fever, and decreased oral intake. The oral examination may find trismus (especially in cases with pterygoid muscle involvement), uvular deviation, palate swelling, and tonsil asymmetry.

Diagnosis is often made by needle aspiration or incision, both painful and invasive methods, and not always reliable.

Ultrasound could play an important role in the differential diagnosis of peritonsillar infections and improve accuracy of real-time needle aspiration.