The medical history of the patient included an allergic food (tomatoes) reaction with glottis edema many years prior. More recently, he had undergone a prostate contrast-enhanced magnetic resonance imaging examination with no adverse reactions. According to the current guidelines developed in 2019 by the Italian Society of Medical Radiology (Società Italiana Radiologia Medica) and the Italian Society of Anesthesia, Analgesia, Resuscitation and Intensive Care (Società Italiana di Anestesia Analgesia Rianimazione e Terapia Intensiva), the patient was not considered at risk for a contrast medium adverse reaction [1,2].

However, during the examination and about 7 minutes after the contrast medium injection, the head CT incidentally showed marked bilateral turbinate hypertrophy associated with diffuse thickening of the nasal and pharyngeal mucosa causing reduction of the airway lumen (Fig. 1).

With the suspicion of acute iodinated contrast medium reaction (AICMR), the patient was promptly examined; he complained about mild rhinitis with nasal congestion. No glottis edema, significant respiratory symptoms, or skin rash occurred. The patient was treated with a combination of antihistamine (clorphenamine) and corticosteroid (betamethasone), and his clinical status quickly improved. After observation, the patient was discharged and did not complain of symptoms in the following days.

Although some cases of small bowel angioedema caused by administration of iodinated contrast medium and demonstrated by abdominal CT have been published [3,4], this is the first case of AICMR documented with a head CT. In our case, the imaging allowed us to suspect AICMR shortly before the patient complained of symptoms. Therefore, we suggest reviewing images of the nasal cavities or upper airways after contrast administration during head CT with the aim of capturing upper airway mucosal change due to allergy and examining its severity.