In this case report, a nine-week-old girl was referred to the ear-, nose- and throat department because of decreased oral intake, swelling of the left tonsil and the left side of the neck. An MRI was performed due to the atypical presentation, which revealed a massive peritonsillar abscess communicating with the swelling on the neck. Treatment consisted of an incision, drainage and intravenous antibiotics. Re-dilation and rinsing were performed on the first post-operative day before extubation. Finally, the patient was discharged after two days with oral antibiotics.