Complications from anaphylaxis are rare, and most patients completely recover. Myocardial ischemia may result from hypotension and hypoxia, particularly when underlying coronary artery disease exists. Ischemia or arrhythmias may result from treatment with pressors. Prolonged hypoxia also may cause brain injury. At times, a fall or other injury may occur when anaphylaxis leads to syncope.
Respiratory failure from severe bronchospasm or laryngeal edema can cause hypoxia, which could lead to brain injury if prolonged.