Despite being widely quoted as having an incidence of 2-30%, multi-phasic anaphylaxis that is clinically significant now appears to have an incidence of about 0.4% for cases of anaphylaxis and 0.1% for cases of allergy in ED patients. Hopefully this will reverse the trend of prolonged observation of patients with non life-threating allergic reactions. This information has been updated in the Anaphylaxis page.