RESUMEN
INTRODUCTION: Anaphylaxis is a severe and life-threatening systemic hypersensitivity reaction. The most frequently encountered causes are foods, drugs, and bee venom, but anaphylaxis may also occur idiopathically. Paradoxical vocal cord movement (PVCM), is a cause of upper airway obstruction due to abnormal adduction of vocal cords during inspiration and, to some degree on expiration. It may be misdiagnosed as asthma or anaphylaxis, and there may be delays in diagnosis. CASE REPORT: We present a 20-year-old male patient with coexistence of urticaria and stridor findings who was evaluated and treated as having idiopathic anaphylaxis but then was diagnosed with PVCM after recurrence of stridor attacks. CONCLUSION: It is useful to bear the diagnosis of PVCM in mind in patients with recurrent and unexplained stridor or in patients with stridor that does not improve despite treatment for another diagnosis such as anaphylaxis. This way, administration of epinephrine, high-dose corticosteroids and interventions such as intubation or tracheostomy can be avoided.